Annals of Internal Medicine

Clinical Guidelines

Screening Mammography in Women 40 to 49 Years of Age: A Systematic Review for the American College of Physicians
Katrina Armstrong, MD, MSCE; Elizabeth Moye, BA; Sankey Williams, MD; Jesse A. Berlin, ScD; and Eileen E. Reynolds, MD

Background: The risks and benefits of mammography screening among women 40 to 49 years of age remain an important issue for clinical practice. Purpose: To evaluate the evidence about the risks and benefits of mammography screening for women 40 to 49 years of age. Data Sources: English-language publications in MEDLINE (1966 – 2005), Pre-MEDLINE, and the Cochrane Central Register of Controlled Trials and references of selected studies through May 2005. Study Selection: Previous systematic reviews; randomized, controlled trials; and observational studies. Data Extraction: Two independent reviewers. Data Synthesis: In addition to publications from the original mammography trials, 117 studies were included in the review. Metaanalyses of randomized, controlled trials demonstrate a 7% to 23% reduction in breast cancer mortality rates with screening mammography in women 40 to 49 years of age. Screening mammography is associated with an increased risk for mastectomy but a decreased

risk for adjuvant chemotherapy and hormone therapy. The risk for death due to breast cancer from the radiation exposure involved in mammography screening is small and is outweighed by a reduction in breast cancer mortality rates from early detection. Rates of falsepositive results are high (20% to 56% after 10 mammograms), but false-positive results have little effect on psychological health or subsequent mammography adherence. Although many women report pain at the time of the mammography, few see pain as a deterrent to future screening. Evidence about the effect of negative screening mammography on