Tailoring Mammography Screening for Women After Age 50

Breast density and breast cancer risk can help guide mammography screening recommendations for women older than age 50 years. In a study published in Annals of Internal Medicine, researchers found that average-risk women with low breast density undergoing screening every 3 years and high-risk women with high breast density undergoing annual screening will derive the same benefit.

For average-risk women-a large proportion of the US population-undergoing mammography every 3 years would decrease the risk of harms, including false-positive mammograms, benign biopsies, and overdiagnosis.

For women who have two to four times the average breast cancer risk level (high-risk women) and heterogeneously or extremely dense breasts, annual screening resulted in a balance of benefits and harms and was found to be cost-effective, according to the study. Benefits of screening include averted death due to breast cancer, life-years gained, and quality-adjusted life-years gained.

The US Preventive Services Task Force currently recommends biennial mammography screening for average-risk women aged 50 to 74 years. The American Cancer Society recommends that women with an average risk of breast cancer undergo annual mammography screening between the ages of 45 and 54 years followed by biennial screening starting at age 55. While clinical trial data and observational and modeling studies support biennial breast cancer screening, data incorporating breast density, breast cancer risk, and personal preferences to guide screening interval choices are limited, according to study authors led by Amy Trentham-Dietz, PhD, of the University of Wisconsin Carbone Cancer Center in Madison.

The authors utilized three previously used models, incorporating breast density, age, and risk of breast cancer. Unlike prior mammography screening models, the team also incorporated a triennial interval, changes in breast density with age, and updated treatment paradigms.

Among women aged 50 to 74 years who have fatty breasts or scattered fibroglandular density, the numbers of breast cancer deaths averted were similar for triennial and biennial screening (median of 3.4 to 5.1 vs 4.1 to 6.5 deaths averted per 1,000 patients screened, respectively). The results were similar for women aged 65 to 74 years (median of 1.5 to 2.1 vs 1.8 to 2.6, respectively).

The median number of breast cancer deaths averted increased with annual vs biennial screening for women aged 50 to 74 years with any breast density. For those women between the ages of 65 and 74 with heterogeneously or extremely dense breasts, the median number of breast cancer deaths averted increased with annual vs biennial screening, but the harms were almost twofold higher.

“Because our results show that the relative risk of breast cancer in combination with breast density has a strong influence on the net benefit of mammography at all screening intervals, evaluation of different risk assessment tools will be important in this context,” concluded the authors.