Estimated benefits and risks of screening for breast cancer

A controlled randomized trial of breast cancer screening has been initiated in Canada. This paper presents an analysis of the possible benefit from screening relative to the possible radiation risk from mammography for those women who will be screened in the trial. It shows that with modern low-dose mammography, even when a conservative estimate of possible reduction in mortality due to early detection is applied to the data, the estimated benefit substantially exceeds any possible hazard.