Benefits of Screening Mammography

Breast cancer is a leading cause of premature death for women in their 40s, and mammographic screening significantly reduces the risk of death due to breast cancer. The latter was the conclusion of the US Preventive Services Task Force (USPSTF) meta-analysis of the randomized controlled trials (RCTs) of screening mammography.1 The USPSTF concluded, however, that the absolute benefit from routine mammographic screening of women in their 40s was too low to offset the harms. As a woman in her 40s, and a radiologist specializing in breast imaging, I find their conclusions puzzling. Randomized controlled trials underestimate the true benefits of mammographic screening.2 They assess mortality reduction among women randomized to the group invited to be screened rather than those who actually participated in screening. In an RCT, an invited woman who never has a mammogram and dies of breast cancer is counted as having been screened, just as a woman in the control group who decides to have a mammogram outside the trial is counted as having not been screened. In several RCTs, mammographic quality was quite poor or only a single mammographic