Reason for Ranking
Evidence suggests that mammography screening reduces breast cancer mortality, especially among older women. A physician’s recommendation or referral—and satisfaction with physicians—are major factors facilitating breast cancer screening. The percent of women ages 40-69 receiving a mammogram is a widely endorsed quality of care measure.
Measurement Strengths and Limitations
Breast cancer is the second most common type of cancer among women in the United States, and cost nearly 7 billion dollars to treat in 2007. The three most common forms of breast cancer screening include self-breast exam, clinical breast exam, and mammogram. Mammograms, which use X-ray to identify breast cancer before a lump can be felt, can increase treatment options, reduce the risk of dying from breast cancer, and reduce the cost of treatment. An estimate based on the most rigorous randomized trials suggests that screening reduces breast cancer mortality by 15%; other estimates suggest reductions of roughly 20-35%.
There is, however, debate around the effectiveness and cost/benefit of regular mammograms for women under 50, and whether screening for breast cancer ultimately does more harm than good. Some researchers point out that while screening reduces breast cancer mortality by 15%, it also leads to 30% overdiagnosis and overtreatment.
Researchers do agree that the sensitivity and specificity of mammograms are highest among older women, and the benefit-to-harm ratio of screening increases as women age because screening accuracy improves and prevalence of breast cancer increases.[1,3] Thus, the Rankings’ use of data on women age 67-69 avoids some of the debated issues summarized above. However, by using data on only this subset of women, this measure may potentially miss trends and disparities among younger age groups.