I co-authored with medical oncologist Dr. Kathleen Pritchard, one of Canada's outstanding medical oncologists in breast cancer, a paper called “Overdiagnosing Overdiagnosis”. The point is that some cancers will grow slowly. For some people, if they didn't know they had cancer, that cancer may not have bothered them before they died of some other cause. The reality is that the fraction of those cancers—these are real cancers, but they're cancers that perhaps grow slowly—is relatively small. It's generally under 10%, and perhaps is in the order of 5%.
The idea is to avoid overtreating those individuals. Once a cancer is diagnosed, try to determine if it's going to be one of the aggressive ones or the less aggressive ones and make therapy suitable for the characteristics of the cancer. I think that's the right approach, rather than not finding the cancer and playing Russian roulette with letting a dangerous cancer continue to grow.