Comments and Response on the USPSTF Recommendation on Screening for Breast Cancer FREE

TO THE EDITOR:

In its evaluation of mammography, the USPSTF (1) recommends screening for breast cancer biennially starting at age 50 years. The USPSTF has stressed that this recommendation depends solely on the tradeoff between medical benefits and harms, with no consideration of costs. Editorials in the Wall Street Journal(2) and New England Journal of Medicine(3), however, suggest that the recommendation was in fact motivated by cost considerations. A careful examination of the data analyses by Mandelblatt and colleagues (4), presented in support of the recommendations, seems to confirm the view that costs were indeed pivotal in informing the USPSTF recommendation.

The USPSTF states that its recommendation involves trading off the mortality benefit of screening against medical “harms,” such as provoked anxiety, the adverse consequences of false-positive results (such as unnecessary biopsies and treatment), and the adverse effects of overdiagnosis. But how did the Task Force use the evidence about these effects to reach its recommendation? No analyses in the report or supporting articles (4 - 5) simultaneously consider both benefits and harms and lead directly to the specific recommendation to begin screening at age 50 years and to do it biennially. Only the Figure in Mandelblatt and colleagues' article (4) includes an analysis that aligns clearly with the USPSTF recommendation.

This figure shows the results of independent analyses by 6 investigative groups of the projected mortality reduction for a range of screening strategies, covering various starting ages, and including options to screen annually or biennially. The critical feature of these analyses is that the population mortality benefit is contrasted solely with the number of mammograms required, a surrogate for resource utilization and thus for costs. The authors do not use the term harms. These analyses search for an optimum strategy at the point where the graphs plateau, representing a point of diminishing returns from additional screening. Biennial screening strategies starting at age 50 years are close to the optimum inflection point in all 6 of these analyses, which seems to be the crucial finding that motivated the USPSTF recommendation.

The number of mammograms in these analyses does not represent “harm.” Rather, it is a measure of the societal investment in mammography (that is, the societal cost). In other words, this is, in effect, a thinly disguised assessment of cost relative to effectiveness, something most experts would label a cost-effectiveness analysis.

Colin B. Begg, PhD

Memorial Sloan-Kettering Cancer Center

New York, NY 10065