Objective: The purpose of this article is to examine the scientific evidence considered by the United States Preventive Services Task Force (USPSTF) in recommending against screening mammography in women 40-49 years old and against annual screening mammography in women 50 and older. We use evidence made available to the USPSTF to estimate the benefits and "harms" of screening mammography in women 40 years old and older. We use Cancer Intervention and Surveillance Modeling Network modeling to compare lives saved by different screening scenarios and the summary of evidence prepared for the USPSTF to estimate the frequency of harms of screening mammography by age.
Conclusion: Averaged over the six Cancer Intervention and Surveillance Modeling Network models of benefit, screening mammography shows greatest benefit--a 39.6% mortality reduction--from annual screening of women 40-84 years old. This screening regimen saves 71% more lives than the USPSTF-recommended regimen of biennial screening of women 50-74 years old, which had a 23.2% mortality reduction. For U.S. women currently 30-39 years old, annual screening mammography from ages 40-84 years would save 99,829 more lives than USPSTF recommendations if all women comply, and 64,889 more lives with the current 65% compliance rate. The potential harms of a screening examination in women 40-49 years old, on average, consist of the risk of a recall for diagnostic workup every 12 years, a negative biopsy every 149 years, a missed breast cancer every 1,000 years, and a fatal radiation-induced breast cancer every 76,000-97,000 years. Evidence made available to the USPSTF strongly supports the mortality benefit of annual screening mammography beginning at age 40 years, whereas potential harms of screening with this regimen are minor.