Comment by mgraczyk
5 days ago
The difference in out come is
With my change: 95% of people who are shown scans have cancer and are treated earlier. 5% of people do not have cancer and get CT scans. 0.5% of people get useless biopsies Without my change: many of those 95% die, the 0.5% do not get useless biopsies
And the beauty of this is you can pick the percentage!
> If you have an growing mass in your body, then after a year, it may very well no longer make a difference whether you treat it or not. Or it may be that you would have lived another 20 years just fine
This is just wrong for many parts of the body. In your brain? Your lungs? Growing for a year between 3 scans 6 months apart? Extremely unlikely to be benign
> 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.
This is wrong. If you had a 100% accurate cancer detector, fewer people would die of cancer with no downside
> With my change: 95% of people who are shown scans have cancer and are treated earlier. Without my change: many of those 95% die
Why? What happens if the cancer still doesn't respond to treatment even when detected early? Or, to the contrary, if the cancer also responds to treatment when it starts becoming symptomatic?
That's why we have studies to understand if screening is a good practice or not. It's not that clear cut.
> With my change: 95% of people who are shown scans have cancer and are treated earlier. 5% of people do not have cancer and get CT scans. 0.5% of people get useless biopsies Without my change: many of those 95% die, the 0.5% do not get useless biopsies
You assume that treating cancer automatically improves the outcome. Treating cancer often kills you, so treating a non-fatal tumor can easily be a bad decision. And a lot of the tumors found by agressive scans are like that, but we don't know yet how much exactly and how to tell one from the other. It's a new question that requires decades-long observations to answer.
> This is wrong. If you had a 100% accurate cancer detector, fewer people would die of cancer with no downside
You're saying it as if detection somehow cures cancer, it doesn't.
> You're saying it as if detection somehow cures cancer, it doesn't.
No, I didn't say the detector would cause cancer to be cured. I said fewer people would die with no downsides. If treatment is sometimes harmful then the detector also fixes that, you'd never treat people without cancer
No, the detector doesn't fix that, that problem is not treating people without cancer. The problem is treating people with cancer that won't kill or harm them during their lifetime. In this case even a low risk treatment becomes harmful, let alone cancer treatments.
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