A COMMENTARY:

"For breast cancer, the incidence of metastatic cancer (cancer that has spread to other parts of the body) was relatively stable since 1975, which indicates that overdiagnosis of harmless breast cancers is likely. For prostate cancer, the volatile incidence rates point to the effects of changes in screening practices over the years, not true cancer rates. In both of these cases, the more we screen for cancer the more we find, making it look like more people have cancer when in reality we are just searching harder. Despite the assertions that breast and prostate cancer screenings “save lives,” Welch et al. find that declines in mortality are more likely due to improvements in cancer treatments rather than early detection efforts"