> The US actually has a higher 5-year survival rate
Take a bunch of people over the age of 50 and then screen them for thyroid cancer. Then don't provide them any treatment at all for that thyroid cancer.
You haven't changed when those people die, nor what they die of, but your 5 year cancer survival rates look good because most of these people will live for more than 5 years with their cancer.
And because there are small risks associated with treatment, if you treat large numbers of people you'll harm small numbers of them. Your 5 year survival rates look good, but your all cause mortality looks worse.
Take a bunch of people over the age of 50 and then screen them for thyroid cancer. Then don't provide them any treatment at all for that thyroid cancer.
You haven't changed when those people die, nor what they die of, but your 5 year cancer survival rates look good because most of these people will live for more than 5 years with their cancer.
And because there are small risks associated with treatment, if you treat large numbers of people you'll harm small numbers of them. Your 5 year survival rates look good, but your all cause mortality looks worse.