The background review for the USPSTF recommendation on screening for breast cancer.

TO THE EDITOR: The recent changes to the U.S. Preventive Services Task Force (USPSTF) breast cancer screening recommendations are welcome and reflect the best available current evidence (1). The updated systematic review by Nelson and colleagues (2), which is the basis for the changes, concurs substantially with the relevant Cochrane review on mammography and, indeed, the Cochrane review of breast self-examination or clinical examination (3, 4). Persons raising concerns about Nelson and colleagues’ review should be reassured that the summary breast cancer mortality reduction of 15% from screening mammography is similar to that presented in the Cochrane review, which was performed independently, and leads to similar estimates of the numbers needed to invite for examination to prevent or delay 1 death from breast cancer. Perhaps the most important addition to the revised USPSTF recommendations is the examination of harms from screening, in particular false-positive results and overdiagnosis. Again, the figures for false-positive results are similar between the 2 reviews and suggest that almost half of U.S. women who have been screened 10 times can expect at least 1 false-positive result with mammography. Both the USPSTF and Cochrane reviews found that overdiagnosis was related to mammography, although the estimation of its frequency varies between the 2 assessments. Evidence-based decision making requires high-quality reliable reviews. The similar findings of Nelson and colleagues’ review and the Cochrane review should be reassuring to women working with their physicians to make evidence-based, informed decisions about screening mammography.