[cactus2093]

Even though those false positive rates are high, I don't think that in itself is enough reason to dismiss the idea.

You'll still be able to identify a pool of people that as a group will develop this cancer at a rate 20x above the normal population. That still seems like a big deal, for instsance if I discovered I had a genetic factor that made me 20x more likely to get a particular cancer I think I would want to be tested for it out of precaution. This seems like the same thing.

(Now if the only further test you can do is itself super invasive or risky, that obviously has to be weighed into the decision too).

[redblacktree]

It's kind of silly to argue from first principles when you can ask the people who study this stuff, epidemiologists. 90% detection and 95% specificity would be horrible numbers if you asked any of them.