Comment by mgraczyk
5 days ago
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
I’ll give you a counter example. I had an MRI of my neck for unrelated reasons. It found a thyroid nodule with suspicious characteristics. Incidentally I had had an MRI of the same areaa few years before and it wasn’t there.
So I had a biopsy. Which was equivocal also.
So I had it out which involved removing half my thyroid. Turns out it was a cancer but like the least serious kind, in fact the classification of it as actual cancer has gone back and forth over the years
But my other half of my thyroid couldn’t produce enough thyroid hormone, and now I have to take thyroid replacement the rest of my life to start alive
Also the surgery affected my voice and I sound like RFK jr now.
I clearly suffered some harm, and even after having the thing out, it’s unclear if that was beneficial at all. A large proportion of these kind of tumors quit growing and never do anything bad. But some do. So who knows.
Was the tradeoff worth it?
I don’t think it’s possible to say
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
No. To argue for the benefit of the procedure, you need to show a difference in outcomes. Not that it can detect something, even if it could (which whole-body MRIs clearly don't). That the detection improves your chances of survival.
If you have an growing mass in your body, then if it's cancer, after a year, it might be too late for treatment. Or it may turn out to be nothing: a benign tumor / cyst / fat deposit in an unusual place. Or it may be slow-growing prostate cancer that you can live with for another 20 years, and maybe it's the chemotherapy that will do you in. It's really not that clear-cut in medicine.
To give you have another example: let's say that the risk of appendicitis in people who have an appendix is 1%. And the risk in people who had an appendix removed is 0%. Does this justify proactively removing the appendix? No, because the consequences of complications are much higher than the harm you're preventing. The same applies here: detection, even if 100% accurate, doesn't mean anything. You need to show that what you do with the result actually helps.
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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
As if there was an easy, foolproof and precise way to calculate these probabilities. "Just only alter the patient when it is appropriate" he said. You can solve all the world's problems this way, just "always do the right thing". Reality, unfortunately, is more complicated.
What if in reality the doctors can only say if the probability is above 60% or not? What if some doctors are better than others at estimating probabilities? What if estimates are influenced by financial reasons by some entity like the hospital or insurer?
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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.
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