> it's _git gud_

There are physical limits to detection and technical parameters that make some situations indeterminate even for the best of the 'gud'. It is frustrating that, hearing an argument from many different individuals over a long time, you assume that each speaker is missing the critical insight that you possess.

> but the tools to make scalable, calibrated risk estimates based on large data dumps is getting better every year.

So your suggestion for indeterminate scans is more scans? There is no 'large data dump' personalized to you except for your own imaging.

> if we can't stop a doctor from doing bad things with a piece of data we should shield them from it

The doctor isn't the problem, it's the people who would be seeking out monthly imaging without symptoms

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bastawhiz 7 hours ago | parent | next [-]

I go to the doctor every year for a checkup without symptoms. Why a year? Why not every six months? Two weeks? Day?

If the false positive rate is demonstrably low, I can't see the risk. People who think they need a doctor will go to a doctor with or without a fancy scan. People who want to play armchair physician will play armchair physician with or without a fancy scan.

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Aurornis 6 hours ago | parent | next [-]

> If the false positive rate is demonstrably low, I can't see the risk

The false positive rate is the entire risk.

When you go to the doctor for a physical they don't run all of the blood tests they can. They only run them for specific symptoms and for specific preventative measures where we've calculated that the benefits outweigh the risks of a false positive.

Some tests have been removed from routine exams, or at least discouraged, because they were producing more false positives and harm than what they were saving.

Full body scans are deep on the end of the spectrum of tests with high false positive rate when ordered without supporting symptoms. That's the risk.

> People who think they need a doctor will go to a doctor with or without a fancy scan. People who want to play armchair physician will play armchair physician with or without a fancy scan.

Not really how it works in real life. When you get a full body scan, especially with ultrasound, there are a lot of benign things that can show up that vaguely look like non-benign things. Even if the interpretation is "probably nothing", many people start worrying and think they need to get more tests just to be safe. Even people who don't see themselves as "armchair physician" will start thinking that they should at least rule out the worst case because they wouldn't want to die of cancer having known that something might have been there.

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bonsai_spool 7 hours ago | parent | prev | next [-]

You can get scans without your normal doctor recommending them. The point is that there is evidence that scans obtained ‘just because’ are harmful as they lead to unnecessary procedures at the population level

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senordevnyc 7 hours ago | parent [-]

But does it also catch more issues early?

	▲	Aurornis 6 hours ago \| parent [-]
		Rarely. More often it leads to people thinking they have issues when they don't. The same thing happens with blood tests: You can order all the blood tests you want if you're willing to pay for them. If you order enough, you will get some that show up as abnormal. You can start spending tens of thousands of dollars ruling things out and never catch any real issues.

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nemomarx 7 hours ago | parent | prev | next [-]

How do you get the false positive rate low? There's a lot of things that look weird on a scan that turn out to be benign. And if you tell patients "well the chance this turns into a serious disease or cancer is low but you can get this optional procedure to fix it now if you want" how many do you think will take them up on it?

A new chargeable procedure is for for the hospital but maybe not for patients imo.

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grey-area 5 hours ago | parent | prev | next [-]

Why do you do it at all?

Many countries with far better outcomes don’t do this, is it necessary, or is it just the product of an insurance-driven health industry which prioritises interventions over health?

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jibal 5 hours ago | parent | prev [-]

> If the false positive rate is demonstrably low

Regardless of how accurate a test is, by Bayes Theorem if it's done on enough healthy people the false positives will swamp the true positives.

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Veedrac 7 hours ago | parent | prev | next [-]

I have libertarian enough tendencies to think that if a person wants to self-operate, or pay for an operation that doctors are telling them is not justified given the evidence, then they should have right to do it. But I don't think that's what people normally mean when they say that eager screening causes harmful overdiagnosis.

> So your suggestion for indeterminate scans is more scans?

The solution to imperfect evidence is consistent and calibrated risk estimation of both disease and intervention.

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bonsai_spool 7 hours ago | parent [-]

The risk estimation is why people aren’t recommended to get scans! There are studies on ‘VIPs’ who get ‘executive MRIs’ and wind up getting treated for things that would never have justified intervention.

	▲	mhb 6 hours ago \| parent \| next [-]
		Isn't the way we decide what justifies intervention by comparing observational data, action and outcomes? Currently our observations are limited by many things including the cost and side effects. More frequent or better observations will improve the assessment of what justifies interventions.
	▲	goda90 7 hours ago \| parent \| prev [-]
		That sounds more like a capitalism issue, to be honest. Treatment = revenue, so of course there will be unscrupulous individuals who will bend their oath and let patient anxiety drive care. The trick seems like it would be to strongly incentivize waiting and watching any symptomless anomalies if further investigation is invasive. If you're getting 60 second scans every month then something growing will be catchable and something static or that disappears can be ignored until the next scan.

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mhl47 6 hours ago | parent | prev [-]

Maybe there is a bias for action within our moral and legal system. Fundamentally if you can deal with uncertainty correctly or "perfectly" wouldn't more information always be better?