According to Robin Hanson, the latter are statistically small.
While cancer screening does consistently lead to more cancer detection and more cancer treatment, it consistently doesn't lead to lower mortality.
This is based on studies of breast cancer, colon cancer, prostate cancer, and lung cancer.
Keep this in mind when someone tells you that other countries have shown how to reduce the cost of health care. No other country is as fanatical as we are about doing cancer screening. My guess is that it is not the magical efficiency of single-payer health care that holds down spending in other countries. Instead, they have chosen not to budget for cancer screening to the extent that we have.
If we adopt a single-payer system here, my guess is that we will not cut back on cancer screening. If anything, we may do more of it.
In Massachusetts, health care reform that was promised to be cost-reducing in fact raised health care spending. I predict that will be true for any health care reform that is not market-oriented. The reformers will project a lower path for spending, and what they will get will be a higher path.