“ One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer.”
This has been my experience. And I’ve had oncologists echo exactly this. In the words of one: MRIs find too much.
The CT and the PET/CT are the gold standards for finding cancer, finding recurrences, and staging cancer. The trouble is the radiation dose.
MRI provides very inconclusive results. You’ll see something but it’ll be unclear what it is. And often what you see is not even visible on a CT. Or it’s visible on a PET/CT and is showing metabolic activity indicating its cancer.
MRIs are great for certain things like herniated disks in your back. They suck at cancer.
It's not that MRIs suck at cancer. They provide fantastic structural and functional data.
The problem is the specificity of the results and the prior.
A full body MRI by definition will provide detailed views of areas where the pretest probability for cancer is negligible. That means even a specific test would result in a high risk of false positives.
As a counter point, MRS means that you can now MRI someone's prostate and do NMR on lesions you find.
Lets say someone has lower urinary tract symptoms. And is 60 years old. An MRI could visualize as well as do a analysis that would otherwise require a biopsy. With the raised prior you can be quite sure suspicious lesions are cancerous.
Similarly for CNS tumours. Where fine detail. Subtle diffusion defects can mark csncers you couldn't even see if you cut the person open.
No sensible doctor would give you a whole body CT unless there was a very good reason. That very good reason is probably "we already think you have disseminated cancer". That pushes the prior up.
And less so for a PET/CT. Lets flood you with x-rays and add some beta radiation and gamma to boot!
The danger of an unnecessary CT/PET is causing cancer, the danger of an unnecessary MRI chasing non existent cancer.
> Lets say someone has lower urinary tract symptoms. And is 60 years old. An MRI could visualize as well as ...
Not a doctor - but maybe start with some quick & cheap tests of their blood & urine, polite questions about their sexual partners, and possibly an ultrasound peek at things?
At least in America, high-tech scans are treated as a cash cow. And cheap & reasonable tests, if done, are merely an afterthought - after the patient has been milked for all the scan-bucks that their insurance will pay out.
> The danger of an unnecessary CT/PET is causing cancer
You'd have to be massively overexposed to CT or PET scanning to cause cancer, like in the region of spending months being scanned continuously with it at full beam current.
> MRIs are great for certain things like herniated disks in your back.
I have had a lot of experience with MRIs on both myself (back and knee [1]) and my dogs with herniated discs. The doctors always make it sound like MRIs are great to confirm what's suspected because of other symptoms like pain, but a point in time MRI alone is not that valuable. Everyone's bodies (including animals!) are surprisingly different inside making normal be somewhat unique. I think what would be interesting is if scanning technology like MRIs could be made so inexpensive and easy that everyone had one done 4x/year. That way it's the differential being checked and I'm guessing it would be way more valuable. Normalization such as this could also lower anxiety around findings.
[1] Even when I tore my ACL the MRI came back only as probable.
Do you know which MRI you used? Not all are equal.
Most MRI are 1.5T powered, and you can’t get fine details until you hit 3T. And there are differences even in the 3T power range. There are higher powered MRI which are mostly only used in research, whilst it is a bit scary thinking about the sheer power of them but a 7T machine doing a full scan of you, would be guaranteed nearly to find anything wrong with you.
When I last looked the full body scans for sale seemed to used 1.5T setup, which seems like a waste. The 3T advanced scans looks much more detailed, but it just depends on where you live - I couldn’t find any around.
One caveat is that regular PET isn't so good in the brain - there is so much metabolic activity that everything glows. So I get an MRI Brain to go with my regular full body PET/CT (cancer 5 years ago with recurrence 18 months later, currently NED).
I had a CT scan last year for some stomach issues they wanted to look at.
Doctor warned me up front that the odds the images find something that looks weird is high but not to panic because of how many false positives there are when looking inside someone’s body.
While I am happy to report they didn’t find anything serious, I do take slight offense to the following at the top of my results:
Last name, First name: Unremarkable
(Kidding of course but still got a chuckle out of me)
2.5 years in of regular PET scans. At this point, I’m almost humored by what gets flagged as suspicious by the radiologist - usually mosquito bites and stomach bugs (kids in daycare means I’m almost always sick). I have a scan Monday and two weeks ago had a re-excision so there’s a two inch gash healing on my back. This week I got three vaccines. And then tonight my toddler bit me hard enough to draw blood. I had asked the oncologist if it made sense to delay the scan because of the re-excision and he said not to worry because he’d know why there’s inflammation in that area. I’m thinking the bite and the shots will probably get flagged too. I just hope I don’t forget any other maladies or mishaps that might get flagged that I can’t explain.
Anecdotal evidence to confirm: I had two false alarms from an unrelated MRI scan, and beside wasting a lot of time on diagnosing them - it was also extremely stressful.
My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment, and it worked twice: early detected lung and prostate tumors, both removed.
> My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment,
These treatments are wonderful and it is great that they exist. But many people fail to understand the difference in terms of pretest probability, etc.
I can absolutely see the heavy psychological impact pending biopsy results may have. People are quick to discount these issues when you raise them as a concern, but only if they never went through this stress themselves
> My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment, and it worked twice: early detected lung and prostate tumors, both removed.
My mum gets scanned a little more frequently than that, following treatment for an inoperable tumour in her lung around five years ago. During treatment she was getting scanned every three months or so, and it was remarkable watching this thing go from the size of a tangerine, to actually expanding a bit and looking "fuzzy" once the drugs kicked in, to being the size of a plum, then the size of a grape attached with a little thin thread of tissue, to being a thing the size of a pea. Now there's a tiny ripple of scar tissue that no-one wants to investigate further, because if it's not doing anything let's not poke at it.
There is a roughly pea-sized "thing" on her adrenal gland that was a bit worrying because anything like that is going to get intimately involved with your lymphatic system and then it's going to metastasise like hell. But it neither got bigger nor smaller in the nearly six years since the first scan, so it can't be that important.
This is one of the great things about the NHS, especially here in Scotland where we have (possibly as a result of the weirdly high levels of cancer) some of the best oncology services in the world.
If we'd lived in the US, the insurance companies would have taken one look at an 83-year-old about to become a grandmother and sent her home with a bottle of morphine to die. As it is, she's doing very well and got to see both her grandchildren start school.
MRIs are good if you know what you’re looking for, and usually with contrast, which in a situation like cancer where you need to do them often can result in allergic reactions.
In a full body situation, they are looking for mets, and the uptake of radioactive sugar by the tumors will let a PET scan find them.
That’s completely and 100% false. It’s much easier to characterize things on MRI and MRI is indeed phenomenal for cancer! The problem is with screening, not actual staging or follow-up, and whole-body screening in ct and pet/ct is even worse than MRI screening even if you ignore radiation.
The argument for better screening would require that finding those asymptomatic cancers actually improves survival rates. There are several reasonable scenarios where early screening doesn't improve it:
* The cancer is aggressive and resistant to treatment. Chemo/radiation only pause the growth for a bit, but ultimately the cancer keeps growing and the total survival time is the same (only that the patient spent more time knowing they had cancer).
* The cancer is susceptible enough to treatment that it's still curable when it becomes symptomatic and found through other means.
* The cancer is slow enough that the patient dies from other causes before.
Early screening brings benefits only when the cancer ends up causing issues and responds differently to treatment between the "early screening detection" time and the "normal detection" time.
It's impossible to know beforehand which of the scenarios have more weight, specially because we have very little data on what happens way before cancer is detected via the usual methods. We need better studies on this, and for now the evidence doesn't really point out to these large, indiscriminate screenings being actually helpful.
That’s not the correct framing - your assertion first lacks evidence about why we should screen better. In fact, we aren’t improving longevity in many early diagnoses, and may be treating people whose immune system would resolve the cancers.
Further, the denominator is asymptomatic people who were able to get MRI’s they didn’t need. That doesn’t tell us anything about the normal world.
I wonder how biased the group is though, is the sample truly representative of the general population or is it a group of people who are already undergoing screen for some other health-related reason?
1. I had a chest x-ray
2. It showed a small dark patch, and my lungs over-inflate.
3. Erring on the side of caution, doctor ordered a lung biopsy.
4. Lung biopsy is painful, annoying, expensive, and non-zero-risk.
5. Lung biopsy turns up nothing. "Maybe you aspirated some food?" We learn nothing.
I don’t understand how you’re concluding that the biopsy shouldn’t have happened from that anecdote? Just because a test result is negative doesn’t mean that it shouldn’t have happened. That’s not how practicing medicine works.
I feel that label is actually deserved. Yes, some cancer types are easier to detect with MRI, in particular inside of a body, but at the same time MRI in and by itself isn't great at predicting all cancer types. How could it help with regards to leukemia, for instance? What exactly could MRI detect here better than other diagnostic tools? One has to keep in mind that diagnosis also takes time - plus the cost; and the overdiagnosis problem which means that some cancer that are not really relevant, are hyped up by MRI to be the end of the world for a patient. So there is a trade-off.
IMO MRI needs to become cheaper; and more reliable too.
No? The point of the article, and of the preceding comments, echoing a pretty common tenet of evidence-based medicine, is that frequent full-body MRIs are a bad idea for the patient.
This guy has never heard the term 'scanxiety'. Go ask what it means on a cancer forum. The real OG's are the VHL folks. Bet we have a few here on this thread. Respect.
Arguments against proactive MRI scanning always seem to have a whiff of status quo bias to them. Yes, right now MRIs are expensive and false positives are common, but if regular scans were widespread, it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives.
To use a software analogy, if your downtime detection system kept producing false negatives, would your solution to be just turn it off? You'd get some better night's sleep, but you'd pay for it when the system really went down and you had no idea.
There's a softer component to healthcare which is that people can overreact to medical results. If a doctor administers a scan, finds a handful of likely benign things but wants to administer another scan later on down the line, I'm probably much more likely to look for a second opinion that tells me to cut them out (even if it may not be medically necessary) than trust my doctor that "it's probably fine".
It's probably more accurate to use a software analogy about performance metrics. We measure random request spikes now and again that strain the system. It's probably fine, but later on down the line, something could change that results in an outage during one of these spikes. Do we proactively fix the problem even if no change is expected? Or do we wait till there is definitely a problem before taking action?
But surely this would decrease as we learned more from more frequent MRI scanning. Doctors and patients would be less likely to overreact, and we'd settle in on something better?
Not to mention the malpractice risk and potential for extra income, which -- depending on where you live -- may strongly (if subconsciously) influence your physicians interpretations and recommendations.
Do you think a doctor is more likely to call something "possible cancer" and recommend that you either have a specialist do a biopsy (keeping in mind that many of these will be... hard to reach) or at least have a follow up MRI in 3, 6, 9 months?
Or tell you it's "pretty unlikely to be cancer, I don't think we need to worry about it" and then get sued for 20M when they are wrong about 1 in 100 cases (not to mention missing out on all the potential income from above).
At least in the US, the incentives here are grossly misaligned.
The major reason not to do this is that you often get worse outcomes for patients. Oncology provides a lot of examples where “more knowledge” does not lead to better outcomes. Routine ovarian cancer screening, prostate screens, childhood neuronlastoma screens, and breast cancer screens all have shown that overuse will identify more cancer, but do not lead to better outcomes like reduced mortality.
The reasons are complex, but the short answer is that cancer treatment is extremely hard on your body, and even if you don’t treat, stress can literally make you sick. I recommend reading The Emperor of all Maladies if you want to really get a sense for how delicate the problem of early screening is.
I’m married to someone running various prostate cancer studies in the UK. I hear the arguments against screening a lot and the issue really blew up recently in the news here.
The thing is, when researchers talk about “worse outcomes” they’re often comparing survival (or rather lack of) against terrible side-effects.
What this fails entirely to capture is that doing something to increase your odds of survival, damn the consequences, is an individual choice. It shouldn’t be up to a health economist to make that judgement.
I appreciate that, but do wonder, if this is an issue with too much data or how we act on that data. In other words, could there be a future where we do have tons more data, but also use the data in such a way to achieve an overall better outcome for patients?
Then they should decide not to treat certain things and have better criteria around that than choosing to bury their heads in the sand and letting people die out of their ignorance.
> it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives.
Why is it likely? We already have a lot of MRI data. There are already a lot of incidental findings. It might also be an issue of the MRI not being able to produce enough information to discriminate.
> To use a software analogy, if your downtime detection system kept producing false negatives, would your solution to be just turn it off? You'd get some better night's sleep, but you'd pay for it when the system really went down and you had no idea.
The analogy is rather something like this: your downtime detector is not just a "ping" but a full web browser that tests everything and it sometimes flags things that are not actually issues. So you don't turn it off, but you only use it when you have another signal that indicates that something might be going wrong.
> Why is it likely? We already have a lot of MRI data. There are already a lot of incidental findings. It might also be an issue of the MRI not being able to produce enough information to discriminate.
This is the main reason. Well technically the opposite of the main reason but more or less it's the same. MRIs are extremely high fidelity nowadays and as a result it's really really hard to read an MRI. Every person is different and there's a lot of variations and weird quirks. You get all the data rather than clearly identified problem areas like you get with say a CT w/ contrast, etc.
That's actually exactly why it's important to have MRIs more frequently to be able to establish baselines and identify trends as they develop.
We do not have a lot of MRI data. The average person probably gets a couple MRIs in their lifetime, and this is biased because we wait until something is clearly wrong to get the MRI. If you want to find an MRI scan of an early stage asymptomatic cancer, the only data on that will be the exceedingly rare case that someone has something else unrelated wrong with them in the same general area and gets an MRI for that, and then just by chance also has the early stage cancer at the same time.
Additional diagnostics can also be very expensive. Articles like this don’t seem to understand the overall costs to a health system with decisions like these. And that cost eventually does go down into the pockets of patients one way or another.
I've seen instances where this is used as an excuse for what is, ostensibly, a trick to dimiss people using something that sounds vaguely professional. Like when doctors say they don't want to do additional x-rays because of the risk of radiation exposure, nvm that if it comes out slightly blurry they'll ask to redo it, or if you're cautious about it initially they'll tell you how it's not big deal and there's more radiation in a cluster of bananas.
> ... if regular scans were widespread, it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives.
And if there's one thing where AI models really do already excel at it's classifying and noticing patterns.
Many dermatologists (not all of them yet, at least not in the EU), for example already have software classifiers using pictures of one's skin and helping guide diagnosis. I've lots of moles/nevi and freckles on my skin: I'm one of those Gen X kids raised by parents that had no idea that sun exposure and sunburns was a bad thing so I regularly get warning shots and my body, especially my back, if full of scars for for my entire life dermatologists have regularly removed concerning little buggers and sent them to the lab for further analysis.
Nowadays my dermatologist is helped in her classification by hardware/software.
I don't see why that wouldn't be the way forward for full scan MRI: they'll begin to be more and more hooked up to AI classifiers.
It always takes time: it's not as if the tech comes out and in 48 hours every hospital/physician is equipped with it.
It's literally the future is here (classifiers helping dermatologists find concerning nevi), just not evenly distributed (many dermatologists still don't have access to these latest machines).
I can't imagine this taking strong hold in the US unless it shields physicians from legal consequences of false negatives or produces enough false positives to ensure revenue doesn't fall.
I don't see any way that the hospital systems running healthcare in the US would embrace a technology that reduces false positives (income) without decreasing false negatives (risk and lost income) at least as much.
> Arguments against proactive MRI scanning always seem to have a whiff of status quo bias to them
More and more European countries are currently adopting Lung Cancer screening programs. It's usually limited to people with a certain amount of cigarette-pack-years, but still gives the opportunity for driving more of the innovation you're talking about. I think the main challenge at the moment is that nothing in healthcare is prepared of looking at those scans effectively, a radiologist has full medical education + additional specialization - without effective procedures you'll never be able to provide full-body scans with any meaningful impact.
It’s expensive because superconducting magnets cryogenically cooled in liquid helium are expensive to build and run. No amount of demand signal will overcome that reality.
Not just cost also time. When I had my scan it took 45 minutes and two trained nurses.
Ofcourse in America poor people don't have access to healthcare so it's a lot easier. But in a universal healthcare system everything has to be rationed.
Most people do have things “wrong” with their body, but they are asymptomatic. The human body can and does cope with a certain amount of failure and/or anomaly as a part of normal operation that we otherwise consider healthy.
The problem is that this information is often not actionable. An MRI is great at identifying which ways your body doesn’t look like a textbook reference body, but it doesn’t necessarily tell you what those things are or whether they will ever cause you problems. The way the body naturally responds to problems doesn’t always look perfect on a scan but if it results in no symptoms it is the best result. And for most asymptomatic findings, taking an invasive next step has more risk than the finding itself. And these findings will always be in the back of the patients head, whether relevant or not, and might complicate how they seek care for other real issues later on.
> An MRI is great at identifying which ways your body doesn’t look like a textbook reference body, but it doesn’t necessarily tell you what those things are or whether they will ever cause you problems.
Its the doctors doing this, not the MRI.
There's this weird definition switch that always happens with the "overdiagnosis" defense where the information gets blamed for the overdiagnosis. An MRI doesn't provide any diagnosis in any sense of the definition. A doctor does.
Claiming an overdiagnosis defense is essentually implying the medical industry is worse for most than doing nothing.
Same logic as not treating the cancer of an 80 year-old as a heuristic rather than looking at the health, genetics, and epigenetics of the individual beyond the chronological age. Whatever happened to "personalized medicine?"
This article sees methodological failure, I see training data. Training data that could ultimately be used to refine low resolution scans into targeted high resolution scans as needed driving down costs and driving up accuracy. We've already demonstrated AI upscaling, what's the blocker to doing the same for MRI?
And finally, who are any of us to tell people what they can do with their money? China has these things down to $70. And they're leaning in hard on improving them. Cue obligatory China cuts corners blah blah blah. Sigh.
> One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer.
So a bit less than 1.8% of the time in this study
> Prenuvo's recent Polaris Study followed 1,011 patients for at least one year following a whole-body MRI scan. Of these patients, 41 had biopsies. More than half of the 41 were diagnosed with cancer.
That's 2.0%
Note that this doesn't mean that 1.7~2.0% of people have cancer without knowing it. It could be more:
> A negative scan doesn’t mean you’re disease-free. Some cancers and conditions simply aren’t visible yet or aren’t reliably detected on a one-time full-body MRI."
But also perhaps less, in a way:
> "You're finding something that never would have caused you any problem in your life, and in cancer, we call that overdiagnosis," Vickers says.
Yep, I have experience with both. It found cancer for my wife and she was able to treat it immediately. Fully recovered.
It found a weird spot on me that turned out to a pancreatic rest.
The only reason we did the scans were because we were making a significant life decision that we didn’t want to have to backtrack if either got diagnosed with cancer within a year . We knew nothing was guaranteed but we wanted to do some tests.
> The only reason we did the scans were because we were making a significant life decision that we didn’t want to have to backtrack if either got diagnosed with cancer within a year .
Interesting. If it's not too personal, would you mind elaborating on the kind of life decision you were making?
I have never heard of anyone getting checked up for cancer before they make an important life decision. I mean won't a cancer diagnosis disrupt your life anyway?
There's a theory that the first-stage cancer is way more common than we think, it's just doesn't develop further most of the time, cause no symptoms and remains undiagnosed throughout the lifetime.
There's some support for this view because agressive screening for thyroid and prostate cancers increases the number of surgeries a lot but doesn't seem affect the mortality rates.
Risks from a surgery are non-negligible, if you perform it to treat a low-risk condition it may be a net loss in the end.
So you're technically right about the "early-detecting" part, but the "much easier to treat" step is problematic because it's unclear what a net-positive treatment looks like for low-risk cases. Probably it comes down to yearly monitoring of whatever was detected, not the actual treatment.
Yes, you could early-detect something, but the likelihood of this thing being life-threatening are extremely low. If you choose to manage this thing aggressively anyway, you have to undergo more invasive testing (e.g., biopsies, surgery, anesthesia, etc.) that all have small risks of catastrophic events. In most cases, the risks of more invasive testing outweigh the risks of just not pursuing any further workup.
Nothing in medicine comes for free—everything is a tradeoff.
> Isn't it possible you could be early-detecting something serious that is much easier to treat now vs when symptoms appear?
It could be. It could also be the cade that you undergo invasive surgery for something that would have never caused you problems within your life. The problem is that cancer isn‘t cancer. Even if it originates from the same tissue, some tumors behave very different from others.
Yeah a 2% risk of having something which can easily kill you and is very expensive to treat, especially if you're not elderly and still have lots of life ahead of your, is not exactly trivial. I would want to know about this
Doctors here are cognitively captured by a system designed to limit cost (and that's mostly a good thing)
But scanning frequently is overwhelmingly good for the patient. The problem is the doctors. Imagine two possibilities.
1. You scan every six months and a doctor reviews your scans but never tells you anything no matter what
2. You scan every six months and a doctor reviews your scans and only tells you results if you have an obviously growing mass that has a probability greater than 95% of being cancerous
Obviously #2 is better for the patient than #1, but #1 is equivalent to never testing if you ignore cost.
So the actual reason we don't have effect frequent scans combined with effective diagnostic techniques is cost, and doctors cope with this reality by saying clearly wrong things about "over diagnosis". It's a local minimum of the payer/provider dynamic that has nothing to do with scans per se.
Why is it good for the patient? I think that to claim this, you'd need to show a difference in outcomes.
Here, you have a tool with a ~100% false positive rate, so if we start administering it to everyone, it will almost certainly cost lives. Botched biopsies, unnecessary treatments, other complications. Not to mention the huge cost that would divert money from other welfare programs. So you need to show that when it actually detects something, it saves at least as many lives. And I doubt that's the case.
I wouldn't argue we should roll this out to everyone. But I am glad it exists. I commented earlier in this topic about how it caught cancer in my wife at the age of 44. She didn't have to go through chemo or radiation treatment because it was caught so early. Surgery removed the whole cancer.
Additionally for me, I have a scan that shows what my body currently has. I had something show up that I did get a scope to check out that was a pancreatic rest. No big deal. Now, if I ever have another MRI and somethings is somewhere else, we have a baseline to compare against. Everything is a risk calculation. When I did my MRI, I also had other procedures done like a heart calcium score.
I will get a little more personal. We didn't do it out of the blue. My wife and I decided we want to live on a sailboat. That was a big purchase for us and boats take a long time to sell. We didn't want to commit to such a purchase then 1 year later find out either of us had cancer then we have the stress of cancer and the stress of trying to sell a boat.
I would never suggest everyone do it, but I am happy we did.
When there is low prevalence of a condition, but a non-zero false positive rate of a test, the false positives generated by universal testing can in fact be a net dis-benefit (worry, invasive further procedures, etc) to the patient population as a whole, regardless of cost. This is a well understood statistical phenomenon, and is carefully considered by healthcare systems when advising on testing.
Tons of diagnostic interventions have been scaled without strong outcome data. For example many clinics now do fractional exhaled nitric oxide (FeNO) tests because they are safe, fairly cheap, and patients often pay directly out of pocket so they are easy to make money on.
But the evidence for the diagnostic usefulness of this test is extremely low, multiple meta analysis have concluded.
The reason FeNO tests are done but not MRIs is because FeNO tests are $40
Your case #2 doesn't have nearly enough information to say whether it's obviously better for a population of patients. There are a lot of other variables you would need to know:
- The accuracy of detecting a mass
- The true distribution of masses in the population
- The likelihood that of falsely detecting a mass in the same place twice (you seem to implicitly assume that false detections are uncorrelated with each other)
- The likelihood that a real mass is cancerous (you stipulate that this is 95% in your scenario, but you don't say what other factors are used to determine this - as opposed to just knowing that there's a mass that grew.)
- The positive effect of treatment in the case of true-positives.
- The negative effect of treatment or further diagnostics in the case of false-positive.
Saying that doctors are lying about over diagnosis to cope with the fact that diagnostic techniques are too expensive is absurd. They have to actually make decisions in the real world, where your two neat little categories can't be known even if they hypothetically exist.
Can someone ELI5 why false positives on a MRI are so bad?
From a pure Bayesian PoV, you're better off with a noisy additional observation. At worst it doesn't get much weight.
At a pragmatic level, can't you say, hey here's something thats probably nothing, let's scan it again in 6 months? Why does an MRI necessarily lead to invasive follow ups?
I get that ideally we'd have a crystal ball with 0 type I / type II errors but short of that, why is a noisy predictor bad?
> At a pragmatic level, can't you say, hey here's something thats probably nothing, let's scan it again in 6 months
If a doctor even _hints_ there might be cancer, the patient will have a terrible 6 months (with actual, measurable negative health impacts of the added stress). Also, at some uncertainy-level (say, 10% chance of cancer) the doctor _has_ to say something and has to schedule expensive followups to not risk liability, even though in 90% of the cases it is not only unnecessary, but actively harmful to the patients.
When, on average, the cost of the screening + the harm done by a false positive outweighs the benefits of an early detection, you shouldn't do the screening in the first place.
This seems super dumb to me. If the test detects cancer that doesn't need treatment, don't treat it!! It's still better to know it's there and that you need to monitor it.
> Before you know it, you are on the operating table having your prostate removed – and we see examples of that all the time,
Well fix that problem then. If someone puts a smoke detector above a toaster you don't just pull the battery and call it a day.
My parents are doctors so I’m very used to giving them all the data and pushing decision making down to them. Almost all of the time there is no action to be taken. But this built a certain habit that I realized is not conducive to medical care in the US.
I once told my wife that it’s better if she just passes all information downstream and then lets the diagnostician do the diagnostics.
During her pregnancy, at antenatal monitoring, when asked the routine questions I encouraged her to mention everything and so she mentioned a slight twinge in her chest (“it’s probably nothing, maybe something I ate”). She was hooked up to the monitors and so on but this was a sudden moment of panic for everyone but us. The nurse called for a doctor, there was an EKG machine brought up, all sorts of honestly nonsensical reaction given the data.
I realized my mistake soon after. There’s the obvious legal consideration, of course, but the real magic lies in the fact that no one gives full information so if someone sends you a signal they assume it’s crossed some threshold to significance. My mistake was in being a non-normative participant here, akin to someone who drives straight on green in a land where a green light means you first let one person turn left before you go.
Anyway, patients are supposed to perform pre-diagnosis in the US. And you’re not supposed to show your doctor things that they will then act on. You should first apply Bayes yourself and then give the info to the doctor here because they won’t use Bayes.
> Well fix that problem then. If someone puts a smoke detector above a toaster you don't just pull the battery and call it a day.
I think what's happening here is that the smoke detector is indicating the possibility of fire, but the toaster is always being immediately doused in water. Which as we know would cause more damage than good unless there truly was a raging inferno.
The suggestion here seems to be moving the smoke detector to somewhere where there's a higher chance of it ringing means a higher chance of a damaging fire. Which seems quite reasonable.
The question is how can you know if it needs treatment or not. I guess you either need to do a biopsy, or check if it's grown after N months (leaving patient scared and anxious during that time). Neither are great if most cases end up not needing treatment.
Because the patient is usually unable to handle such information correctly (the medical system sometimes too). And the whole-body-scan type of tests additionally pre-select for the high anxiety types.
I pay an extra $60 a year to have my ophthalmologist take a digital image of my retina. It comes back as normal every year, but if something does change we can diff the image against the baseline.
Maybe I don't want to look for cancer right now but if I spend $1,000 every 5 years to take an image for later use... isn't that useful?
Yes, and it seems like its purposefully ignored in the "body scan" debate. full CT scans would be more problematic, and MRI's (especially no contrast ones) don't pick up a lot of things... but having annual comparisons over a few years would likely fill in some of those gaps. literally and figuratively.
Might be, but in the context it's also worth asking what better options you have for your health with that $1000.
(for some people that question may not apply, of course, but at a population level it does, and we have population-level questions about effective use of MRI time.). And if there's something better, you should spend it on that and then ask the question _again_. So it could be that getting a whole-body MRI is something like $30k down the list of best ways to spend money for improved health.
I'm not sure what the best use of $1k is from a health standpoint is, just noting that it's good to have a comparator.
> I'm not sure what the best use of $1k is from a health standpoint is, just noting that it's good to have a comparator.
Spending 1k on a gym membership and more fresh vegetables would be a pretty high return on investment, if one isn't in shape and eating healthy already.
One important point is that many people die WITH cancer but not OF cancer. So even for the 1.8%, only a fraction of those people were going to die of the disease (or even suffer significant symptoms) - the rest were just going to die of natural causes anyway.
But now you've found it you pretty much have to remove it, which has significant quality of life implications.
Age is a big factor in the with/of cancer factor. If someone is 80 years old then there's good chance it won't be cancer that kills them (assuming they aren't already in a late stage).
But if you are 40 and you have cancer, there's a good chance you'll die of that cancer if it's left untreated.
I'm personally of the opinion that cancer screening should happen earlier for younger people and less frequently for older people. Like, if you hit 80, there's really basically no reason to screen for cancer.
It does, doesn't it! This is basically the reason scepticism in screening has risen (amongst scientists and medics, not the general population) - research seems to show that screening catches much more cancer but doesn't save many more people.
Rohin Francis does a good video on it, which you don't have to watch because it has references underneath you can click straight through to (the video is good though): https://youtu.be/yNzQ_sLGIuA
I am frustrated by this because it seems obvious to me that "more data == better" but I guess it makes sense if you think of the scans as having high amounts of noise, and us having a poor understanding of the system we're monitoring (this never happens in tech, of course :)).
From the statistics on autopsy and other accidental discovery, it seems that more than 30% of the population has some cancer by age 40 that would never impact their life left untreated (mostly thyroid, prostate, and surprisingly-for-me, breast cancer). Regular widespread full body MRI might catch these, but the effects of treating (e.g.) prostate cancer are so terrible that most would be better off ignoring it.
Maybe the right answer isn't to do a biopsy, but to monitor the area with follow-up scans? It seems like that addresses much of the harm that a false positive can cause (invasive biopsy leading to complications) while maintaining most of the gains (still very early detection).
The problem is that just because you‘re detecting something, it does not mean it is worth watching. Bodies are not standardized and most people habe something off. But you can‘t really reschedule everybody constantly, as that would entirely break the concept.
"Worth watching" implies that watching is expensive. It's really not. A full-body MRI scan is about $1k, and it can be even cheaper.
So if you have abnormal findings in 10% of patients that merit follow-up scans, you can trivially do a series of 3-4 scans without affecting the overall cost too much.
Doctors simply need to get out of the headspace where MRIs are extremely scarce tools of last resort and treat them like we treat blood tests.
> Maybe the right answer isn't to do a biopsy, but to monitor the area with follow-up scans?
Doctors have already thought of this. Several issues with it:
* Monitoring still causes anxiety and mental health issues which come with real effects on patient's quality of life. It's not "harmless".
* Unclear when to monitor and when to treat. It's also really hard to get enough data to characterize these early unspecific findings enough to get confidence on what to do.
* Monitoring via MRI might be just as useful as monitoring via symptoms or any other "passive" methods that do not require a previous scan.
There are two points in MRIs that limit or (better) regulate their use:
* financial cost vs level of care. A full body MRI costs a huge sum but it is the most detailed non-invasive diagnosis we have for any disease that can lead to earlier therapy. Used as a screening method, does it worth to save one patient in tens/hundreds tests performed? You answer, but public health authorities, health insurances and medical societies are negative.
* MRI shows some minor findings that would never cause symptoms and better not be known to the patient due to the stress they bring and cost of ongoing follow up (eg in the brain small meningiomas or angiomas). This might bring more harm than good and limit their net value.
For some reason, I always found the arguments for "it's better to not know" for these tests to be strange and slightly infantilizing. But of course this must not be the end of it, and there might be some more well thought out arguments from bioethicists that go beyond "the patient can't handle the truth". Because this argument seems like it's doing a lot of heavy lifting without much evidence.
> One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer
So that would be 1.71% of people getting a full body MRI catching cancer early.
That seems like an astoundingly good return to me. What does late cancer treatment and lost lives cost? Many times these MRI’s.
If everyone did this, would there be any significant number of late stage cancer discoveries anymore?
Obviously, reducing the cost of false positives is important. But if 1.7% of us have cancer - wow. My guess is that percentage can be tuned up and down by demographics. So maybe there is still an argument against everyone doing it.
Many of those cancers are not harmful or would be killed ok their own. And the cost of diagnosis on the patient is not free either. It causes lots of anxiety and stress which also cause large negative health effects too. Over diagnosis is real and also bad. Medical stuff is just really hard
There’s a major difference between having insurance cover something (socialized cost, immediately drives up provider fees for bizarre reasons) and letting the market allow people to buy it themselves (individual cost, the market drives the cost down fast and hard). Notice the pattern with LASIK and GLP1 where lack of insurance coverage has counterintuitively made it cheaper and more accessible.
Let everyone who wants to pay get their scans! But don’t make me pay for you
Can one solution be always doing two scans, N months apart, before drawing any conclusions (excluding things that can be reliably detected from a single scan)? Initial scan could affect N (if you find something potentially aggressive, you can schedule the second scan sooner). And then do a follow up every M years.
That should exclude benign or very slowing growing things
Extremely anecdotal: my dad’s lung cancer was found incidentally - shoulder pain → shoulder MRI → radiologist noticed lung nodules. The shoulder pain was unrelated, but the scan itself was clinically indicated and there were prior scans to compare against, which made it immediately suspicious and triggered follow-up imaging.
He was also in a higher-risk group (age + history), which in hindsight probably made the incidental finding meaningful rather than noise.
So cases like his make me think less “scan everyone periodically” and more “imaging can be very valuable once risk is non-trivial or there’s a baseline to compare to”. For the general population you’d mostly generate false positives, but for higher-risk groups (older, smokers, prior findings) it seems much more defensible.
Wrt the issue at hand: yes the cancer was found as an incidental finding on a scan performed for another indication (shoulder pain) -> the question remains whether your father benefitted from finding the cancer. This is seldomly the case.
Anecdotally, everything is possible but on a population scale, actual survival benefit is rare - whereas suffering from the downsides is not - even if only counting unnecessary healthcare cost and time wasted.
In my dad’s case it very likely did - it was lung cancer and still pre-symptomatic, but had already started to metastasize, so a later discovery would probably have meant a much worse prognosis category.
I agree anecdotes don’t generalize and broad population screening sounds like a bad tradeoff.
What I’m wondering about instead is risk-stratified situations: once someone already has elevated risk or prior lung disease and you’re imaging them periodically for legitimate reasons, incidental findings may carry much more signal than noise.
For example, people with prior tuberculosis often get periodic chest X-rays, not to screen the general population, but because their baseline risk is different. My dad had prior lung disease and existing imaging to compare against, which probably made the finding actionable rather than just another false positive.
So not “scan everyone”, more “the usefulness of incidental findings rises quickly once pre-test probability isn’t tiny”.
Just to point out, cancer isn't the only reason to get these. Aneurisms, hemachromatosis, etc can all be serious. I know someone who got scanned for $500 and they caught hemachromatosis via iron deposits in the liver. Much better than eventual chirrosis and liver failure.
If you get the MRI you are performing simultaneous blind tests for a thousand rare, unsuspected conditions. The blood test only tests for one of them, and eats 10ml of blood. There isn't enough blood in your body for all those tests.
We should arguably be, in an ideal healthcare system, getting annual MRIs with the other typical tests in a physical, and feeding that data into an AI, and have the AI issue recommendations for informed hazard & secondary testing/biopsy priorities. Tomographic analysis and differential diagnosis is exactly the sort of multidimensional pattern recognition task an AI is great at compared to a human doctor, if you can provide the training data.
Normalizing an annual MRI is the biomedical equivalent to survey astronomy and opening up those gargantuan datasets - you expect lots of simultaneous serendipitous discoveries in unrelated areas without securing an organizational mandate to fund a dedicated research effort into each one of them. The worst the process is ever going to be diagnostically is right now before we're collecting any data in a concerted fashion - every bit of training improves it.
A blood test doesn't scan for other issues. A genetic test and iron study is going to run a few hundred dollars. Add in the cumulative cost for the other conditions checked for, like aneurism, and a $500 MRI isn't that bad.
MRI does not diagnose hemachromatosis. It detects iron deposits (could be due to other harmful issues). To my knowledge it would not produce a false positive. Hemachromatosis is the most common genetic issue in white people, so pretty common (I'm too lazy to look up stats).
I much prefer tests with low false positive rates.
I recently had such a cancer-related test. A cousin had a BRCA2 mutation and I was concerned I could have it also. Insurance would not pay for the testing, but one can get a panel of such genetic tests for just $250 now, so I went ahead. And it was negative. This is reassuring not just to me, but also to my children, and (somewhat) my sibling (the relevant parent is no longer alive).
Had this test been positive, the chance of pancreatic cancer would have gone way up, so frequent scans (I think annual MRI and ultrasound?) would have been justified.
People often contain features in their body that look abnormal on an MRI but might not actually be issues. The issue is that an MRI doesn’t give enough information to know otherwise. This is why they are typically not used in a routine exam by mainstream medicine.
It’s like running ‘ls -la’ on a directory to determine if there are any issues with a piece of software. It could show things that are really bad. It could show things that look weird. But it won’t conclusively debug the code.
I don't see the point of testing constantly. It's just creating stress and probably most of the time, the tumor might be benign or it might be small and go away on its own.
And anyway, you have to die of something so for me cancer would just be a sign that time's up.
> The tests range from several hundred to several thousand dollars, depending on which sections of the body are scanned, and are not covered by insurance.
Even ignoring the overdiagnosing problem (I don't understand how they can determine from MRI when a cancer is a cancer; there are also benign growth and often when they are a certain size, people notice them, but how would MRI help here? Too small areas could be classified as malign; any further procedures can be dangerous - see that Dawson Creek actor recently, the cost of clinical intervention did not help), I think that medicine is increasingly becoming a "only affordable for those who have money". You can see this with regards to gene therapy too - if we ignore the success ratio, many of these therapies are impossible to acquire for Average Joe. Granted, the prices will go down for various reasons (we saw this with Moore's law and many other inventions too), but at the end of the day I feel we are stepping closer and closer to a very unfair society model - more and more superrich, but prices also go up immensely for average people. That model is not sustainable; people will be angry since this is not fair.
Frankly, this sounds like some people aren't so comfortable with the sheer cost of the machine than their absolute utility. CT and MRI scan machines are something that said to cost like $1m/yr/unit that's ~$500 uninsured/$100 insured per run in Japan that China don't publish data on numbers or distributions of. That says "military grade expensive" written all over.
Doctors absolutely hate the idea of people being checked for diseases. Every time someone comes out with a plan to detect cancer or prevent HIV, they start screeching.
“But what if the person would have died anyway without noticing they had cancer? Think of the shareholders. They would have paid for treatment for nothing”
“ One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer.”
This has been my experience. And I’ve had oncologists echo exactly this. In the words of one: MRIs find too much.
The CT and the PET/CT are the gold standards for finding cancer, finding recurrences, and staging cancer. The trouble is the radiation dose.
MRI provides very inconclusive results. You’ll see something but it’ll be unclear what it is. And often what you see is not even visible on a CT. Or it’s visible on a PET/CT and is showing metabolic activity indicating its cancer.
MRIs are great for certain things like herniated disks in your back. They suck at cancer.
It's not that MRIs suck at cancer. They provide fantastic structural and functional data.
The problem is the specificity of the results and the prior.
A full body MRI by definition will provide detailed views of areas where the pretest probability for cancer is negligible. That means even a specific test would result in a high risk of false positives.
As a counter point, MRS means that you can now MRI someone's prostate and do NMR on lesions you find.
Lets say someone has lower urinary tract symptoms. And is 60 years old. An MRI could visualize as well as do a analysis that would otherwise require a biopsy. With the raised prior you can be quite sure suspicious lesions are cancerous.
Similarly for CNS tumours. Where fine detail. Subtle diffusion defects can mark csncers you couldn't even see if you cut the person open.
No sensible doctor would give you a whole body CT unless there was a very good reason. That very good reason is probably "we already think you have disseminated cancer". That pushes the prior up.
And less so for a PET/CT. Lets flood you with x-rays and add some beta radiation and gamma to boot!
The danger of an unnecessary CT/PET is causing cancer, the danger of an unnecessary MRI chasing non existent cancer.
> Lets say someone has lower urinary tract symptoms. And is 60 years old. An MRI could visualize as well as ...
Not a doctor - but maybe start with some quick & cheap tests of their blood & urine, polite questions about their sexual partners, and possibly an ultrasound peek at things?
At least in America, high-tech scans are treated as a cash cow. And cheap & reasonable tests, if done, are merely an afterthought - after the patient has been milked for all the scan-bucks that their insurance will pay out.
Source: Bitter personal experience.
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> The danger of an unnecessary CT/PET is causing cancer
You'd have to be massively overexposed to CT or PET scanning to cause cancer, like in the region of spending months being scanned continuously with it at full beam current.
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> MRIs are great for certain things like herniated disks in your back.
I have had a lot of experience with MRIs on both myself (back and knee [1]) and my dogs with herniated discs. The doctors always make it sound like MRIs are great to confirm what's suspected because of other symptoms like pain, but a point in time MRI alone is not that valuable. Everyone's bodies (including animals!) are surprisingly different inside making normal be somewhat unique. I think what would be interesting is if scanning technology like MRIs could be made so inexpensive and easy that everyone had one done 4x/year. That way it's the differential being checked and I'm guessing it would be way more valuable. Normalization such as this could also lower anxiety around findings.
[1] Even when I tore my ACL the MRI came back only as probable.
Do you know which MRI you used? Not all are equal. Most MRI are 1.5T powered, and you can’t get fine details until you hit 3T. And there are differences even in the 3T power range. There are higher powered MRI which are mostly only used in research, whilst it is a bit scary thinking about the sheer power of them but a 7T machine doing a full scan of you, would be guaranteed nearly to find anything wrong with you.
When I last looked the full body scans for sale seemed to used 1.5T setup, which seems like a waste. The 3T advanced scans looks much more detailed, but it just depends on where you live - I couldn’t find any around.
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Spot on. And dealing with false positives sucks.
One caveat is that regular PET isn't so good in the brain - there is so much metabolic activity that everything glows. So I get an MRI Brain to go with my regular full body PET/CT (cancer 5 years ago with recurrence 18 months later, currently NED).
I had a CT scan last year for some stomach issues they wanted to look at.
Doctor warned me up front that the odds the images find something that looks weird is high but not to panic because of how many false positives there are when looking inside someone’s body.
While I am happy to report they didn’t find anything serious, I do take slight offense to the following at the top of my results:
Last name, First name: Unremarkable
(Kidding of course but still got a chuckle out of me)
> I do take slight offense to the following at the top of my results:
No offense for me, just confusion. One of the status reports started as follows:
> OptionOfT is a very pleasant 36-year-old gentleman 6 weeks status post left anterior total hip arthroplasty done by Dr. _ on _.
I asked my wife whether I was particularly friendly (I sometimes fail to adjust my demeanor in certain situations).
She said: nah, they write that for everybody.
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2.5 years in of regular PET scans. At this point, I’m almost humored by what gets flagged as suspicious by the radiologist - usually mosquito bites and stomach bugs (kids in daycare means I’m almost always sick). I have a scan Monday and two weeks ago had a re-excision so there’s a two inch gash healing on my back. This week I got three vaccines. And then tonight my toddler bit me hard enough to draw blood. I had asked the oncologist if it made sense to delay the scan because of the re-excision and he said not to worry because he’d know why there’s inflammation in that area. I’m thinking the bite and the shots will probably get flagged too. I just hope I don’t forget any other maladies or mishaps that might get flagged that I can’t explain.
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Anecdotal evidence to confirm: I had two false alarms from an unrelated MRI scan, and beside wasting a lot of time on diagnosing them - it was also extremely stressful.
My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment, and it worked twice: early detected lung and prostate tumors, both removed.
> My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment,
These treatments are wonderful and it is great that they exist. But many people fail to understand the difference in terms of pretest probability, etc.
I can absolutely see the heavy psychological impact pending biopsy results may have. People are quick to discount these issues when you raise them as a concern, but only if they never went through this stress themselves
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> My father is a part of "full body PET scan every 3 years" program as part of post - cancer treatment, and it worked twice: early detected lung and prostate tumors, both removed.
My mum gets scanned a little more frequently than that, following treatment for an inoperable tumour in her lung around five years ago. During treatment she was getting scanned every three months or so, and it was remarkable watching this thing go from the size of a tangerine, to actually expanding a bit and looking "fuzzy" once the drugs kicked in, to being the size of a plum, then the size of a grape attached with a little thin thread of tissue, to being a thing the size of a pea. Now there's a tiny ripple of scar tissue that no-one wants to investigate further, because if it's not doing anything let's not poke at it.
There is a roughly pea-sized "thing" on her adrenal gland that was a bit worrying because anything like that is going to get intimately involved with your lymphatic system and then it's going to metastasise like hell. But it neither got bigger nor smaller in the nearly six years since the first scan, so it can't be that important.
This is one of the great things about the NHS, especially here in Scotland where we have (possibly as a result of the weirdly high levels of cancer) some of the best oncology services in the world.
If we'd lived in the US, the insurance companies would have taken one look at an 83-year-old about to become a grandmother and sent her home with a bottle of morphine to die. As it is, she's doing very well and got to see both her grandchildren start school.
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“MRIs…suck at cancer”
Wrong? I understand MRIs are the standard for certain types of cancer like brain and spinal tumors.
With respect to whole body MRI they can be less effective because it’s not optimized, accuracy can be traded for area.
But as a general statement MRIs do not suck at cancer.
MRIs are good if you know what you’re looking for, and usually with contrast, which in a situation like cancer where you need to do them often can result in allergic reactions.
In a full body situation, they are looking for mets, and the uptake of radioactive sugar by the tumors will let a PET scan find them.
That’s completely and 100% false. It’s much easier to characterize things on MRI and MRI is indeed phenomenal for cancer! The problem is with screening, not actual staging or follow-up, and whole-body screening in ct and pet/ct is even worse than MRI screening even if you ignore radiation.
>One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer.
That can also be reframed as 1.71% of asymptomatic people having cancer, which is a really good argument for better screening.
The argument for better screening would require that finding those asymptomatic cancers actually improves survival rates. There are several reasonable scenarios where early screening doesn't improve it:
* The cancer is aggressive and resistant to treatment. Chemo/radiation only pause the growth for a bit, but ultimately the cancer keeps growing and the total survival time is the same (only that the patient spent more time knowing they had cancer).
* The cancer is susceptible enough to treatment that it's still curable when it becomes symptomatic and found through other means.
* The cancer is slow enough that the patient dies from other causes before.
Early screening brings benefits only when the cancer ends up causing issues and responds differently to treatment between the "early screening detection" time and the "normal detection" time.
It's impossible to know beforehand which of the scenarios have more weight, specially because we have very little data on what happens way before cancer is detected via the usual methods. We need better studies on this, and for now the evidence doesn't really point out to these large, indiscriminate screenings being actually helpful.
That’s not the correct framing - your assertion first lacks evidence about why we should screen better. In fact, we aren’t improving longevity in many early diagnoses, and may be treating people whose immune system would resolve the cancers.
Further, the denominator is asymptomatic people who were able to get MRI’s they didn’t need. That doesn’t tell us anything about the normal world.
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I wonder how biased the group is though, is the sample truly representative of the general population or is it a group of people who are already undergoing screen for some other health-related reason?
Not because of an MRI, but this happened to me:
N=1, but that biopsy should not have happened.
I don’t understand how you’re concluding that the biopsy shouldn’t have happened from that anecdote? Just because a test result is negative doesn’t mean that it shouldn’t have happened. That’s not how practicing medicine works.
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>MRIs are great for certain things like herniated disks in your back. They suck at cancer.
MRIs are fine for certain kinds of cancer like liver cancer.
But saying MRIs "suck at cancer" feels off. They're actually first-line or gold standard for certain cancers
I feel that label is actually deserved. Yes, some cancer types are easier to detect with MRI, in particular inside of a body, but at the same time MRI in and by itself isn't great at predicting all cancer types. How could it help with regards to leukemia, for instance? What exactly could MRI detect here better than other diagnostic tools? One has to keep in mind that diagnosis also takes time - plus the cost; and the overdiagnosis problem which means that some cancer that are not really relevant, are hyped up by MRI to be the end of the world for a patient. So there is a trade-off.
IMO MRI needs to become cheaper; and more reliable too.
hmm that is still around 1.5% of ppl having cancer. not trivial. Even more if you include false negatives.
I mean, i think you need to look more into it than that.
If you make a test that always returns true, it would also meet that criteria.
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And yes getting frequent full body MRIs is still overwhelming the right thing for the patient.
No? The point of the article, and of the preceding comments, echoing a pretty common tenet of evidence-based medicine, is that frequent full-body MRIs are a bad idea for the patient.
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This guy has never heard the term 'scanxiety'. Go ask what it means on a cancer forum. The real OG's are the VHL folks. Bet we have a few here on this thread. Respect.
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Here in NZ an Australia, the college of radiologists disagree and say ‘don’t do it’ for screening the worried well.
https://www.ranzcr.com/college/document-library/2024-positio...
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Arguments against proactive MRI scanning always seem to have a whiff of status quo bias to them. Yes, right now MRIs are expensive and false positives are common, but if regular scans were widespread, it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives.
To use a software analogy, if your downtime detection system kept producing false negatives, would your solution to be just turn it off? You'd get some better night's sleep, but you'd pay for it when the system really went down and you had no idea.
There's a softer component to healthcare which is that people can overreact to medical results. If a doctor administers a scan, finds a handful of likely benign things but wants to administer another scan later on down the line, I'm probably much more likely to look for a second opinion that tells me to cut them out (even if it may not be medically necessary) than trust my doctor that "it's probably fine".
It's probably more accurate to use a software analogy about performance metrics. We measure random request spikes now and again that strain the system. It's probably fine, but later on down the line, something could change that results in an outage during one of these spikes. Do we proactively fix the problem even if no change is expected? Or do we wait till there is definitely a problem before taking action?
But surely this would decrease as we learned more from more frequent MRI scanning. Doctors and patients would be less likely to overreact, and we'd settle in on something better?
I'm not an expert though.
No, this is more like disabling logging because people are concerned the server is going down.
“Don’t worry about it, I don’t think it’s a real issue so we’re just going to ignore it”
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Not to mention the malpractice risk and potential for extra income, which -- depending on where you live -- may strongly (if subconsciously) influence your physicians interpretations and recommendations.
Do you think a doctor is more likely to call something "possible cancer" and recommend that you either have a specialist do a biopsy (keeping in mind that many of these will be... hard to reach) or at least have a follow up MRI in 3, 6, 9 months?
Or tell you it's "pretty unlikely to be cancer, I don't think we need to worry about it" and then get sued for 20M when they are wrong about 1 in 100 cases (not to mention missing out on all the potential income from above).
At least in the US, the incentives here are grossly misaligned.
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The major reason not to do this is that you often get worse outcomes for patients. Oncology provides a lot of examples where “more knowledge” does not lead to better outcomes. Routine ovarian cancer screening, prostate screens, childhood neuronlastoma screens, and breast cancer screens all have shown that overuse will identify more cancer, but do not lead to better outcomes like reduced mortality.
The reasons are complex, but the short answer is that cancer treatment is extremely hard on your body, and even if you don’t treat, stress can literally make you sick. I recommend reading The Emperor of all Maladies if you want to really get a sense for how delicate the problem of early screening is.
I’m married to someone running various prostate cancer studies in the UK. I hear the arguments against screening a lot and the issue really blew up recently in the news here.
The thing is, when researchers talk about “worse outcomes” they’re often comparing survival (or rather lack of) against terrible side-effects.
What this fails entirely to capture is that doing something to increase your odds of survival, damn the consequences, is an individual choice. It shouldn’t be up to a health economist to make that judgement.
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I appreciate that, but do wonder, if this is an issue with too much data or how we act on that data. In other words, could there be a future where we do have tons more data, but also use the data in such a way to achieve an overall better outcome for patients?
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Then they should decide not to treat certain things and have better criteria around that than choosing to bury their heads in the sand and letting people die out of their ignorance.
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> it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives.
Why is it likely? We already have a lot of MRI data. There are already a lot of incidental findings. It might also be an issue of the MRI not being able to produce enough information to discriminate.
> To use a software analogy, if your downtime detection system kept producing false negatives, would your solution to be just turn it off? You'd get some better night's sleep, but you'd pay for it when the system really went down and you had no idea.
The analogy is rather something like this: your downtime detector is not just a "ping" but a full web browser that tests everything and it sometimes flags things that are not actually issues. So you don't turn it off, but you only use it when you have another signal that indicates that something might be going wrong.
> Why is it likely? We already have a lot of MRI data. There are already a lot of incidental findings. It might also be an issue of the MRI not being able to produce enough information to discriminate.
This is the main reason. Well technically the opposite of the main reason but more or less it's the same. MRIs are extremely high fidelity nowadays and as a result it's really really hard to read an MRI. Every person is different and there's a lot of variations and weird quirks. You get all the data rather than clearly identified problem areas like you get with say a CT w/ contrast, etc.
That's actually exactly why it's important to have MRIs more frequently to be able to establish baselines and identify trends as they develop.
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We do not have a lot of MRI data. The average person probably gets a couple MRIs in their lifetime, and this is biased because we wait until something is clearly wrong to get the MRI. If you want to find an MRI scan of an early stage asymptomatic cancer, the only data on that will be the exceedingly rare case that someone has something else unrelated wrong with them in the same general area and gets an MRI for that, and then just by chance also has the early stage cancer at the same time.
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> We already have a lot of MRI data.
That's true but not in a useful way for improving MRI screening.
What we have is lots of days from people who were sent to get an MRI because they had a complaint.
That's a very different group than people doing screening.
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False positives trigger more diagnostics some of which can be harmful, not just psychologically but physiologically as well.
If false positives are ok, why not build a down time detector that rolls a die every 5 mins and alert on hitting a 6.
Additional diagnostics can also be very expensive. Articles like this don’t seem to understand the overall costs to a health system with decisions like these. And that cost eventually does go down into the pockets of patients one way or another.
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> some of which can be harmful,
Like what?
I've seen instances where this is used as an excuse for what is, ostensibly, a trick to dimiss people using something that sounds vaguely professional. Like when doctors say they don't want to do additional x-rays because of the risk of radiation exposure, nvm that if it comes out slightly blurry they'll ask to redo it, or if you're cautious about it initially they'll tell you how it's not big deal and there's more radiation in a cluster of bananas.
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Harmful to shareholder value.
Personally I’d rather have cancer checked out rather than have a “wait and die” approach
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> ... if regular scans were widespread, it's likely this result in innovations that would drive down costs, improve accuracy, as well as producing a much larger corpus of data with which to guide diagnosis and reduce false positives.
And if there's one thing where AI models really do already excel at it's classifying and noticing patterns.
Many dermatologists (not all of them yet, at least not in the EU), for example already have software classifiers using pictures of one's skin and helping guide diagnosis. I've lots of moles/nevi and freckles on my skin: I'm one of those Gen X kids raised by parents that had no idea that sun exposure and sunburns was a bad thing so I regularly get warning shots and my body, especially my back, if full of scars for for my entire life dermatologists have regularly removed concerning little buggers and sent them to the lab for further analysis.
Nowadays my dermatologist is helped in her classification by hardware/software.
I don't see why that wouldn't be the way forward for full scan MRI: they'll begin to be more and more hooked up to AI classifiers.
It always takes time: it's not as if the tech comes out and in 48 hours every hospital/physician is equipped with it.
It's literally the future is here (classifiers helping dermatologists find concerning nevi), just not evenly distributed (many dermatologists still don't have access to these latest machines).
I can't imagine this taking strong hold in the US unless it shields physicians from legal consequences of false negatives or produces enough false positives to ensure revenue doesn't fall.
I don't see any way that the hospital systems running healthcare in the US would embrace a technology that reduces false positives (income) without decreasing false negatives (risk and lost income) at least as much.
> Arguments against proactive MRI scanning always seem to have a whiff of status quo bias to them
More and more European countries are currently adopting Lung Cancer screening programs. It's usually limited to people with a certain amount of cigarette-pack-years, but still gives the opportunity for driving more of the innovation you're talking about. I think the main challenge at the moment is that nothing in healthcare is prepared of looking at those scans effectively, a radiologist has full medical education + additional specialization - without effective procedures you'll never be able to provide full-body scans with any meaningful impact.
It's helpful in justifying screening that non-small cell lung cancer treatments have greatly improved in recent years.
It’s expensive because superconducting magnets cryogenically cooled in liquid helium are expensive to build and run. No amount of demand signal will overcome that reality.
Not just cost also time. When I had my scan it took 45 minutes and two trained nurses.
Ofcourse in America poor people don't have access to healthcare so it's a lot easier. But in a universal healthcare system everything has to be rationed.
But medicine isn't quite the same feedback loop as downtime monitoringg
This isn’t just about false positives.
Most people do have things “wrong” with their body, but they are asymptomatic. The human body can and does cope with a certain amount of failure and/or anomaly as a part of normal operation that we otherwise consider healthy.
The problem is that this information is often not actionable. An MRI is great at identifying which ways your body doesn’t look like a textbook reference body, but it doesn’t necessarily tell you what those things are or whether they will ever cause you problems. The way the body naturally responds to problems doesn’t always look perfect on a scan but if it results in no symptoms it is the best result. And for most asymptomatic findings, taking an invasive next step has more risk than the finding itself. And these findings will always be in the back of the patients head, whether relevant or not, and might complicate how they seek care for other real issues later on.
> An MRI is great at identifying which ways your body doesn’t look like a textbook reference body, but it doesn’t necessarily tell you what those things are or whether they will ever cause you problems.
Its the doctors doing this, not the MRI.
There's this weird definition switch that always happens with the "overdiagnosis" defense where the information gets blamed for the overdiagnosis. An MRI doesn't provide any diagnosis in any sense of the definition. A doctor does.
Claiming an overdiagnosis defense is essentually implying the medical industry is worse for most than doing nothing.
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Same logic as not treating the cancer of an 80 year-old as a heuristic rather than looking at the health, genetics, and epigenetics of the individual beyond the chronological age. Whatever happened to "personalized medicine?"
This article sees methodological failure, I see training data. Training data that could ultimately be used to refine low resolution scans into targeted high resolution scans as needed driving down costs and driving up accuracy. We've already demonstrated AI upscaling, what's the blocker to doing the same for MRI?
And finally, who are any of us to tell people what they can do with their money? China has these things down to $70. And they're leaning in hard on improving them. Cue obligatory China cuts corners blah blah blah. Sigh.
Answering the question in the title...
> One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer.
So a bit less than 1.8% of the time in this study
> Prenuvo's recent Polaris Study followed 1,011 patients for at least one year following a whole-body MRI scan. Of these patients, 41 had biopsies. More than half of the 41 were diagnosed with cancer.
That's 2.0%
Note that this doesn't mean that 1.7~2.0% of people have cancer without knowing it. It could be more:
> A negative scan doesn’t mean you’re disease-free. Some cancers and conditions simply aren’t visible yet or aren’t reliably detected on a one-time full-body MRI."
But also perhaps less, in a way:
> "You're finding something that never would have caused you any problem in your life, and in cancer, we call that overdiagnosis," Vickers says.
Yep, I have experience with both. It found cancer for my wife and she was able to treat it immediately. Fully recovered.
It found a weird spot on me that turned out to a pancreatic rest.
The only reason we did the scans were because we were making a significant life decision that we didn’t want to have to backtrack if either got diagnosed with cancer within a year . We knew nothing was guaranteed but we wanted to do some tests.
> The only reason we did the scans were because we were making a significant life decision that we didn’t want to have to backtrack if either got diagnosed with cancer within a year .
Interesting. If it's not too personal, would you mind elaborating on the kind of life decision you were making?
I have never heard of anyone getting checked up for cancer before they make an important life decision. I mean won't a cancer diagnosis disrupt your life anyway?
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> You're finding something that never would have caused you any problem in your life
Is it though? Isn't it possible you could be early-detecting something serious that is much easier to treat now vs when symptoms appear?
There's a theory that the first-stage cancer is way more common than we think, it's just doesn't develop further most of the time, cause no symptoms and remains undiagnosed throughout the lifetime.
There's some support for this view because agressive screening for thyroid and prostate cancers increases the number of surgeries a lot but doesn't seem affect the mortality rates.
Risks from a surgery are non-negligible, if you perform it to treat a low-risk condition it may be a net loss in the end.
So you're technically right about the "early-detecting" part, but the "much easier to treat" step is problematic because it's unclear what a net-positive treatment looks like for low-risk cases. Probably it comes down to yearly monitoring of whatever was detected, not the actual treatment.
Yes, you could early-detect something, but the likelihood of this thing being life-threatening are extremely low. If you choose to manage this thing aggressively anyway, you have to undergo more invasive testing (e.g., biopsies, surgery, anesthesia, etc.) that all have small risks of catastrophic events. In most cases, the risks of more invasive testing outweigh the risks of just not pursuing any further workup.
Nothing in medicine comes for free—everything is a tradeoff.
> Isn't it possible you could be early-detecting something serious that is much easier to treat now vs when symptoms appear?
It could be. It could also be the cade that you undergo invasive surgery for something that would have never caused you problems within your life. The problem is that cancer isn‘t cancer. Even if it originates from the same tissue, some tumors behave very different from others.
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Yeah a 2% risk of having something which can easily kill you and is very expensive to treat, especially if you're not elderly and still have lots of life ahead of your, is not exactly trivial. I would want to know about this
That's not the case. Most of these wouldn't kill you. Many of those that would kill you would be spotted in time anyways.
And the few that would kill you and would otherwise not be noticed are so rare that the risk of the procedures on the others is considered higher.
Doctors here are cognitively captured by a system designed to limit cost (and that's mostly a good thing)
But scanning frequently is overwhelmingly good for the patient. The problem is the doctors. Imagine two possibilities. 1. You scan every six months and a doctor reviews your scans but never tells you anything no matter what 2. You scan every six months and a doctor reviews your scans and only tells you results if you have an obviously growing mass that has a probability greater than 95% of being cancerous
Obviously #2 is better for the patient than #1, but #1 is equivalent to never testing if you ignore cost.
So the actual reason we don't have effect frequent scans combined with effective diagnostic techniques is cost, and doctors cope with this reality by saying clearly wrong things about "over diagnosis". It's a local minimum of the payer/provider dynamic that has nothing to do with scans per se.
Why is it good for the patient? I think that to claim this, you'd need to show a difference in outcomes.
Here, you have a tool with a ~100% false positive rate, so if we start administering it to everyone, it will almost certainly cost lives. Botched biopsies, unnecessary treatments, other complications. Not to mention the huge cost that would divert money from other welfare programs. So you need to show that when it actually detects something, it saves at least as many lives. And I doubt that's the case.
I wouldn't argue we should roll this out to everyone. But I am glad it exists. I commented earlier in this topic about how it caught cancer in my wife at the age of 44. She didn't have to go through chemo or radiation treatment because it was caught so early. Surgery removed the whole cancer.
Additionally for me, I have a scan that shows what my body currently has. I had something show up that I did get a scope to check out that was a pancreatic rest. No big deal. Now, if I ever have another MRI and somethings is somewhere else, we have a baseline to compare against. Everything is a risk calculation. When I did my MRI, I also had other procedures done like a heart calcium score.
I will get a little more personal. We didn't do it out of the blue. My wife and I decided we want to live on a sailboat. That was a big purchase for us and boats take a long time to sell. We didn't want to commit to such a purchase then 1 year later find out either of us had cancer then we have the stress of cancer and the stress of trying to sell a boat.
I would never suggest everyone do it, but I am happy we did.
You are deep in the cope here.
There is no world in which biopsies cause more harm than detecting every cancer at stage 1 prevents.
> Not to mention the huge cost that would divert money from shareholders
Ah, that explains it
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Did you read my two options? Do you agree option 2 is better than option 1? If so, then scans are better than no scan
You don't need to show that it's possible to avoid false positives. That's doctors being irrational.
You only need to show that it's possible to build a diagnostic system that's better than no testing, and I have shown that already
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No.
When there is low prevalence of a condition, but a non-zero false positive rate of a test, the false positives generated by universal testing can in fact be a net dis-benefit (worry, invasive further procedures, etc) to the patient population as a whole, regardless of cost. This is a well understood statistical phenomenon, and is carefully considered by healthcare systems when advising on testing.
Read my #2 option, which accounts for that
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I don't think this is doctors being captured by the system so much as medicine being cautious about scaling interventions without strong outcome data
Nope, this is cope
Tons of diagnostic interventions have been scaled without strong outcome data. For example many clinics now do fractional exhaled nitric oxide (FeNO) tests because they are safe, fairly cheap, and patients often pay directly out of pocket so they are easy to make money on.
But the evidence for the diagnostic usefulness of this test is extremely low, multiple meta analysis have concluded.
The reason FeNO tests are done but not MRIs is because FeNO tests are $40
"First, do no harm."
Your case #2 doesn't have nearly enough information to say whether it's obviously better for a population of patients. There are a lot of other variables you would need to know:
Saying that doctors are lying about over diagnosis to cope with the fact that diagnostic techniques are too expensive is absurd. They have to actually make decisions in the real world, where your two neat little categories can't be known even if they hypothetically exist.
Best comment here
Can someone ELI5 why false positives on a MRI are so bad?
From a pure Bayesian PoV, you're better off with a noisy additional observation. At worst it doesn't get much weight.
At a pragmatic level, can't you say, hey here's something thats probably nothing, let's scan it again in 6 months? Why does an MRI necessarily lead to invasive follow ups?
I get that ideally we'd have a crystal ball with 0 type I / type II errors but short of that, why is a noisy predictor bad?
> At a pragmatic level, can't you say, hey here's something thats probably nothing, let's scan it again in 6 months
If a doctor even _hints_ there might be cancer, the patient will have a terrible 6 months (with actual, measurable negative health impacts of the added stress). Also, at some uncertainy-level (say, 10% chance of cancer) the doctor _has_ to say something and has to schedule expensive followups to not risk liability, even though in 90% of the cases it is not only unnecessary, but actively harmful to the patients.
When, on average, the cost of the screening + the harm done by a false positive outweighs the benefits of an early detection, you shouldn't do the screening in the first place.
I 100% agree. The UK recently recommended to not scan for prostate cancer because it sometimes detects cancers that don't need treatment:
https://www.bbc.com/news/articles/cm20169gz44o.amp
This seems super dumb to me. If the test detects cancer that doesn't need treatment, don't treat it!! It's still better to know it's there and that you need to monitor it.
> Before you know it, you are on the operating table having your prostate removed – and we see examples of that all the time,
Well fix that problem then. If someone puts a smoke detector above a toaster you don't just pull the battery and call it a day.
My parents are doctors so I’m very used to giving them all the data and pushing decision making down to them. Almost all of the time there is no action to be taken. But this built a certain habit that I realized is not conducive to medical care in the US.
I once told my wife that it’s better if she just passes all information downstream and then lets the diagnostician do the diagnostics.
During her pregnancy, at antenatal monitoring, when asked the routine questions I encouraged her to mention everything and so she mentioned a slight twinge in her chest (“it’s probably nothing, maybe something I ate”). She was hooked up to the monitors and so on but this was a sudden moment of panic for everyone but us. The nurse called for a doctor, there was an EKG machine brought up, all sorts of honestly nonsensical reaction given the data.
I realized my mistake soon after. There’s the obvious legal consideration, of course, but the real magic lies in the fact that no one gives full information so if someone sends you a signal they assume it’s crossed some threshold to significance. My mistake was in being a non-normative participant here, akin to someone who drives straight on green in a land where a green light means you first let one person turn left before you go.
Anyway, patients are supposed to perform pre-diagnosis in the US. And you’re not supposed to show your doctor things that they will then act on. You should first apply Bayes yourself and then give the info to the doctor here because they won’t use Bayes.
> Well fix that problem then. If someone puts a smoke detector above a toaster you don't just pull the battery and call it a day.
I think what's happening here is that the smoke detector is indicating the possibility of fire, but the toaster is always being immediately doused in water. Which as we know would cause more damage than good unless there truly was a raging inferno.
The suggestion here seems to be moving the smoke detector to somewhere where there's a higher chance of it ringing means a higher chance of a damaging fire. Which seems quite reasonable.
The question is how can you know if it needs treatment or not. I guess you either need to do a biopsy, or check if it's grown after N months (leaving patient scared and anxious during that time). Neither are great if most cases end up not needing treatment.
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> If the test detects cancer that doesn't need treatment, don't treat it!!
How do you know which ones to treat and which ones to leave?
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My understanding is it's liability, if the doctor decides not to look into it then they could be blamed for it if it turns to cancer.
Because the patient is usually unable to handle such information correctly (the medical system sometimes too). And the whole-body-scan type of tests additionally pre-select for the high anxiety types.
In real life, every additional data point has a cost...
I pay an extra $60 a year to have my ophthalmologist take a digital image of my retina. It comes back as normal every year, but if something does change we can diff the image against the baseline.
Maybe I don't want to look for cancer right now but if I spend $1,000 every 5 years to take an image for later use... isn't that useful?
Yes, and it seems like its purposefully ignored in the "body scan" debate. full CT scans would be more problematic, and MRI's (especially no contrast ones) don't pick up a lot of things... but having annual comparisons over a few years would likely fill in some of those gaps. literally and figuratively.
Might be, but in the context it's also worth asking what better options you have for your health with that $1000.
(for some people that question may not apply, of course, but at a population level it does, and we have population-level questions about effective use of MRI time.). And if there's something better, you should spend it on that and then ask the question _again_. So it could be that getting a whole-body MRI is something like $30k down the list of best ways to spend money for improved health.
I'm not sure what the best use of $1k is from a health standpoint is, just noting that it's good to have a comparator.
> I'm not sure what the best use of $1k is from a health standpoint is, just noting that it's good to have a comparator.
Spending 1k on a gym membership and more fresh vegetables would be a pretty high return on investment, if one isn't in shape and eating healthy already.
Er wait is retinal cancer a thing?
Yes. Like OP, I do a picture every year. Three years ago there was a scare, that turned out to be nothing.
Retinal imaging is used to detect damage from glaucoma or other eye disease, by "diffing" the fine blood vessels and nerves.
Family history of glaucoma and macular degeneration. Also had a semi detached retina when I was a kid.
Yes. You can also have melanoma on your uvea
theres a ton of degeneative stuff too that's not strongly age corrilated.
One important point is that many people die WITH cancer but not OF cancer. So even for the 1.8%, only a fraction of those people were going to die of the disease (or even suffer significant symptoms) - the rest were just going to die of natural causes anyway.
But now you've found it you pretty much have to remove it, which has significant quality of life implications.
This seems like a wild statement.
Age is a big factor in the with/of cancer factor. If someone is 80 years old then there's good chance it won't be cancer that kills them (assuming they aren't already in a late stage).
But if you are 40 and you have cancer, there's a good chance you'll die of that cancer if it's left untreated.
I'm personally of the opinion that cancer screening should happen earlier for younger people and less frequently for older people. Like, if you hit 80, there's really basically no reason to screen for cancer.
It does, doesn't it! This is basically the reason scepticism in screening has risen (amongst scientists and medics, not the general population) - research seems to show that screening catches much more cancer but doesn't save many more people.
Rohin Francis does a good video on it, which you don't have to watch because it has references underneath you can click straight through to (the video is good though): https://youtu.be/yNzQ_sLGIuA
I am frustrated by this because it seems obvious to me that "more data == better" but I guess it makes sense if you think of the scans as having high amounts of noise, and us having a poor understanding of the system we're monitoring (this never happens in tech, of course :)).
From the statistics on autopsy and other accidental discovery, it seems that more than 30% of the population has some cancer by age 40 that would never impact their life left untreated (mostly thyroid, prostate, and surprisingly-for-me, breast cancer). Regular widespread full body MRI might catch these, but the effects of treating (e.g.) prostate cancer are so terrible that most would be better off ignoring it.
Maybe the right answer isn't to do a biopsy, but to monitor the area with follow-up scans? It seems like that addresses much of the harm that a false positive can cause (invasive biopsy leading to complications) while maintaining most of the gains (still very early detection).
The problem is that just because you‘re detecting something, it does not mean it is worth watching. Bodies are not standardized and most people habe something off. But you can‘t really reschedule everybody constantly, as that would entirely break the concept.
"Worth watching" implies that watching is expensive. It's really not. A full-body MRI scan is about $1k, and it can be even cheaper.
So if you have abnormal findings in 10% of patients that merit follow-up scans, you can trivially do a series of 3-4 scans without affecting the overall cost too much.
Doctors simply need to get out of the headspace where MRIs are extremely scarce tools of last resort and treat them like we treat blood tests.
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> Maybe the right answer isn't to do a biopsy, but to monitor the area with follow-up scans?
Doctors have already thought of this. Several issues with it:
* Monitoring still causes anxiety and mental health issues which come with real effects on patient's quality of life. It's not "harmless".
* Unclear when to monitor and when to treat. It's also really hard to get enough data to characterize these early unspecific findings enough to get confidence on what to do.
* Monitoring via MRI might be just as useful as monitoring via symptoms or any other "passive" methods that do not require a previous scan.
There are two points in MRIs that limit or (better) regulate their use:
* financial cost vs level of care. A full body MRI costs a huge sum but it is the most detailed non-invasive diagnosis we have for any disease that can lead to earlier therapy. Used as a screening method, does it worth to save one patient in tens/hundreds tests performed? You answer, but public health authorities, health insurances and medical societies are negative.
* MRI shows some minor findings that would never cause symptoms and better not be known to the patient due to the stress they bring and cost of ongoing follow up (eg in the brain small meningiomas or angiomas). This might bring more harm than good and limit their net value.
For some reason, I always found the arguments for "it's better to not know" for these tests to be strange and slightly infantilizing. But of course this must not be the end of it, and there might be some more well thought out arguments from bioethicists that go beyond "the patient can't handle the truth". Because this argument seems like it's doing a lot of heavy lifting without much evidence.
“slightly infantilizing” might be an appropriate course given how well LLM sycophancy works on the general populace.
> One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding, but just 1.8% of these findings were indeed cancer
So that would be 1.71% of people getting a full body MRI catching cancer early.
That seems like an astoundingly good return to me. What does late cancer treatment and lost lives cost? Many times these MRI’s.
If everyone did this, would there be any significant number of late stage cancer discoveries anymore?
Obviously, reducing the cost of false positives is important. But if 1.7% of us have cancer - wow. My guess is that percentage can be tuned up and down by demographics. So maybe there is still an argument against everyone doing it.
Many of those cancers are not harmful or would be killed ok their own. And the cost of diagnosis on the patient is not free either. It causes lots of anxiety and stress which also cause large negative health effects too. Over diagnosis is real and also bad. Medical stuff is just really hard
There’s a major difference between having insurance cover something (socialized cost, immediately drives up provider fees for bizarre reasons) and letting the market allow people to buy it themselves (individual cost, the market drives the cost down fast and hard). Notice the pattern with LASIK and GLP1 where lack of insurance coverage has counterintuitively made it cheaper and more accessible.
Let everyone who wants to pay get their scans! But don’t make me pay for you
It seems like the key missing piece is long-term randomized data showing mortality benefit and cost-effectiveness in average-risk populations
Can one solution be always doing two scans, N months apart, before drawing any conclusions (excluding things that can be reliably detected from a single scan)? Initial scan could affect N (if you find something potentially aggressive, you can schedule the second scan sooner). And then do a follow up every M years.
That should exclude benign or very slowing growing things
Extremely anecdotal: my dad’s lung cancer was found incidentally - shoulder pain → shoulder MRI → radiologist noticed lung nodules. The shoulder pain was unrelated, but the scan itself was clinically indicated and there were prior scans to compare against, which made it immediately suspicious and triggered follow-up imaging.
He was also in a higher-risk group (age + history), which in hindsight probably made the incidental finding meaningful rather than noise.
So cases like his make me think less “scan everyone periodically” and more “imaging can be very valuable once risk is non-trivial or there’s a baseline to compare to”. For the general population you’d mostly generate false positives, but for higher-risk groups (older, smokers, prior findings) it seems much more defensible.
Sorry to hear about your dad.
Wrt the issue at hand: yes the cancer was found as an incidental finding on a scan performed for another indication (shoulder pain) -> the question remains whether your father benefitted from finding the cancer. This is seldomly the case.
Anecdotally, everything is possible but on a population scale, actual survival benefit is rare - whereas suffering from the downsides is not - even if only counting unnecessary healthcare cost and time wasted.
In my dad’s case it very likely did - it was lung cancer and still pre-symptomatic, but had already started to metastasize, so a later discovery would probably have meant a much worse prognosis category.
I agree anecdotes don’t generalize and broad population screening sounds like a bad tradeoff. What I’m wondering about instead is risk-stratified situations: once someone already has elevated risk or prior lung disease and you’re imaging them periodically for legitimate reasons, incidental findings may carry much more signal than noise.
For example, people with prior tuberculosis often get periodic chest X-rays, not to screen the general population, but because their baseline risk is different. My dad had prior lung disease and existing imaging to compare against, which probably made the finding actionable rather than just another false positive.
So not “scan everyone”, more “the usefulness of incidental findings rises quickly once pre-test probability isn’t tiny”.
Just to point out, cancer isn't the only reason to get these. Aneurisms, hemachromatosis, etc can all be serious. I know someone who got scanned for $500 and they caught hemachromatosis via iron deposits in the liver. Much better than eventual chirrosis and liver failure.
A blood test is a far cheaper way to check this.
No it isn't.
If you get the MRI you are performing simultaneous blind tests for a thousand rare, unsuspected conditions. The blood test only tests for one of them, and eats 10ml of blood. There isn't enough blood in your body for all those tests.
We should arguably be, in an ideal healthcare system, getting annual MRIs with the other typical tests in a physical, and feeding that data into an AI, and have the AI issue recommendations for informed hazard & secondary testing/biopsy priorities. Tomographic analysis and differential diagnosis is exactly the sort of multidimensional pattern recognition task an AI is great at compared to a human doctor, if you can provide the training data.
Normalizing an annual MRI is the biomedical equivalent to survey astronomy and opening up those gargantuan datasets - you expect lots of simultaneous serendipitous discoveries in unrelated areas without securing an organizational mandate to fund a dedicated research effort into each one of them. The worst the process is ever going to be diagnostically is right now before we're collecting any data in a concerted fashion - every bit of training improves it.
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A blood test doesn't scan for other issues. A genetic test and iron study is going to run a few hundred dollars. Add in the cumulative cost for the other conditions checked for, like aneurism, and a $500 MRI isn't that bad.
What's the base rate of hemachromatosis in the population and what's the false positive rate for MRI detection of the condition?
MRI does not diagnose hemachromatosis. It detects iron deposits (could be due to other harmful issues). To my knowledge it would not produce a false positive. Hemachromatosis is the most common genetic issue in white people, so pretty common (I'm too lazy to look up stats).
I much prefer tests with low false positive rates.
I recently had such a cancer-related test. A cousin had a BRCA2 mutation and I was concerned I could have it also. Insurance would not pay for the testing, but one can get a panel of such genetic tests for just $250 now, so I went ahead. And it was negative. This is reassuring not just to me, but also to my children, and (somewhat) my sibling (the relevant parent is no longer alive).
Had this test been positive, the chance of pancreatic cancer would have gone way up, so frequent scans (I think annual MRI and ultrasound?) would have been justified.
> One study in 2020 found that 95% of asymptomatic patients had some type of "abnormal" finding
Call me naïve but why don't we just update our definition of "(ab)normal" then?
People often contain features in their body that look abnormal on an MRI but might not actually be issues. The issue is that an MRI doesn’t give enough information to know otherwise. This is why they are typically not used in a routine exam by mainstream medicine.
It’s like running ‘ls -la’ on a directory to determine if there are any issues with a piece of software. It could show things that are really bad. It could show things that look weird. But it won’t conclusively debug the code.
1. collecting baseline info for later comparison is good
2. i can afford the money for the chance of early detection. Many cancers are symptomatic only in the latter stages. It does not hurt to check.
I don't see the point of testing constantly. It's just creating stress and probably most of the time, the tumor might be benign or it might be small and go away on its own.
And anyway, you have to die of something so for me cancer would just be a sign that time's up.
> The tests range from several hundred to several thousand dollars, depending on which sections of the body are scanned, and are not covered by insurance.
Even ignoring the overdiagnosing problem (I don't understand how they can determine from MRI when a cancer is a cancer; there are also benign growth and often when they are a certain size, people notice them, but how would MRI help here? Too small areas could be classified as malign; any further procedures can be dangerous - see that Dawson Creek actor recently, the cost of clinical intervention did not help), I think that medicine is increasingly becoming a "only affordable for those who have money". You can see this with regards to gene therapy too - if we ignore the success ratio, many of these therapies are impossible to acquire for Average Joe. Granted, the prices will go down for various reasons (we saw this with Moore's law and many other inventions too), but at the end of the day I feel we are stepping closer and closer to a very unfair society model - more and more superrich, but prices also go up immensely for average people. That model is not sustainable; people will be angry since this is not fair.
Link for users outside of US: https://archive.ph/7qWCf
if you are getting an MRI for some acute condition, I wonder what the marginal cost to 'upgrade' to a 'full body scan' is?
Frankly, this sounds like some people aren't so comfortable with the sheer cost of the machine than their absolute utility. CT and MRI scan machines are something that said to cost like $1m/yr/unit that's ~$500 uninsured/$100 insured per run in Japan that China don't publish data on numbers or distributions of. That says "military grade expensive" written all over.
Any numbers on practical pricing per country for these scans?
is it necessary?
[dead]
Doctors absolutely hate the idea of people being checked for diseases. Every time someone comes out with a plan to detect cancer or prevent HIV, they start screeching.
“But what if the person would have died anyway without noticing they had cancer? Think of the shareholders. They would have paid for treatment for nothing”