[tptacek]

This seems like yet another place where the base rate is going to fuck us: intuitively (and you've actually thought about this problem and I haven't) I'd expect that even with remarkably good tests, most people who come up positive will not go on to develop related disease.

[rscho]

Ideally, you'd want a test (or two sequential ones) that's both very sensitive (rule candidates in) and specific (rule healthy peeps out). But that's only the first step, because there's no point knowing you're sick (from the populational and economic pov) if you can't do something useful about it. So you also have to include downstream tests and treatments in your assessment and all this suddenly becomes a very intricate probability network needing lots of data and thinking before decisions are made. And then, there's politics...

[Spooky23]

You might be able to target and preemptively treat some aggressive cancers!

I lost my wife to melanoma that metastasized to her brain after cancerous mole and margin was removed 4 years earlier. They did due diligence and by all signs there was no evidence of recurrence, until there was. They think that the tumor appeared 2-3 months before symptoms (headaches) appeared, so it was unlikely that you’d discover it otherwise.

With something like this, maybe you could get lower dose immunotherapy that would help your body eradicate the cancer?

[tptacek]

I'm so sorry about your wife.

Literally anything that reduces cancer deaths is a win. I'm certainly not campaigning against early detection tests like this! Just talking about a challenge that comes up operationalizing them.

[Spooky23]

No worries. I did not take it that way! There’s definitely a line with this stuff where there’s no benefit. But if we can eliminate deadly cancers where detection is difficult, we’ve saved the lives of thousands of people.