So the old thought about cancer was "every cancer will grow and kill the patient so we always want to find the cancer early and treat it before it spreads" Tur

So the old thought about cancer was "every cancer will grow and kill the patient so we always want to find the cancer early and treat it before it spreads" Turns out that's not accurate, and its complicated, and we are still learning. There's three types of cancer, birds, turtles, and rabbits. (I didn't make up this terminology, see links) The birds have already flown away and left the barnyard, early detection isn't going to help. The rabbits need to be contained before they hop away, if we shut the barnyard gate early enough we can prevent their escape. These are the cancers where early detection is useful and saves lives. The turtles just chill out, moving so slow that they never escape. These cancers cause no symptoms and will not go on to ever harm the patient and may even resolve themselves over time. Finding turtles is bad, treating turtles causes very serious side effects (cancer treatment isn't exactly benign), wastes time and money, causes anxiety, and doesn't reduce mortality one bit. We've discovered there's a lot of turtles out there. Of course, once we find early stage cancer we usually treat it like its a rabbit, even if its destined to be a turtle, because a lot of the time we can't tell the difference. South Korea is finding this out the hard way, aggressive screening for thyroid cancer has produced a TON of thyroid cancer patients (15-fold increase (!) over the past 20 years) but ZERO reduction in thyroid cancer mortality. https://sciencebasedmedicine.org/a-skeptical-look-at-screening-tests/ https://sciencebasedmedicine.org/a-skeptical-look-at-screeni... https://fivethirtyeight.com/features/the-case-against-early-cancer-detection/ https://fivethirtyeight.com/features/the-case-against-early-... https://www.skepdoc.info/a-skeptical-look-at-screening-tests-2/ https://www.skepdoc.info/a-skeptical-look-at-screening-tests...