Personalizing Mammography by Breast Density and Other Risk Factors

July 5, 2011

The results of an analysis estimating the cost-effectiveness of mammography by age, breast density (the strongest risk factor for breast cancer), history of breast biopsy, family history of breast cancer, and screening interval were published this week in the Annals of Internal Medicine.  Based on the results, the authors recommend that all women have an initial screening at age 40 to assess breast density, and then develop a schedule for mammography based on individual risk factors and a woman’s personal beliefs about the potential benefit and harms of screening.  According to Dr. Steven R. Cummings, senior author of the study and senior researcher at the California Pacific Medical Center Research Institute, “Previous guidelines are trying to make one-size-fits-all, while we think of this as a personalized approach.”

The study was based on a computer simulation model comparing the lifetime costs and health benefits for women who got mammograms every year, every two years, every three to four years or never.   The outcome measures of the study were the costs per quality-adjusted life-year (QALY) gained and number of women screened over 10 years to prevent 1 death from breast cancer.  Considering false-positive mammography results and the costs of detecting cancers that are ultimately nonprogressive and nonlethal, results showed that annual mammography was not cost-effective for any woman, regardless of age or breast density.

On the other hand, mammography every two years was beneficial for many groups of women with a wide range of individual risk factors.  In women aged 40 to 49 years with high breast density and either a previous breast biopsy or a first-degree relative with breast cancer, biennial mammography was beneficial.  But for women ages 50 to 79 with low breast density and no other risk factors, mammography every three to four years was cost-effective. The authors did not include genetics in their analysis, and therefore the results are not applicable to carriers of BRCA1 or BRCA2 mutations.