Overdiagnosing overdiagnosis

Solid evidence shows that screening mammography contributes to a substantial reduction in mortality from breast cancer, but it is far from a perfect test. Estimates of overdetection of breast cancer, based on extrapolation of SEER data, may suffer from considerable uncertainty because of major assumptions required in such calculations and the difficulty in correcting for confounding factors such as lead time and demographic variations. Some of the charged language used and the extreme positions taken in the discussion of screening distract from coherent communication of the complex issues surrounding this topic. More balanced discussion would better serve the public.