I dunno -- Yvain here seems to have a good point:

If a doctor uses the established thresholds and refers a patient to surgery that turns out to be unnecessary, there are laws preventing that patient from suing her. The same is true if all the tests came back below the threshold, she said he was fine, and he later turned out to be super unlucky and have a totally undetectable form of cancer. The doctor did everything right. She just got unlucky. Those laws are really good. If they didn't exist, it would either be impossible to practice medicine, or else doctors would be optimizing for not being sued rather than for doing good medicine even more than they already are. If they only existed in one direction (eg doctors who did unnecessary surgeries couldn't be sued, but doctors who missed cancer could), that would be even worse - any doctor not heroic enough to go against her own self-interest would refer every patient to surgery.

[emphasis as in the original]