Tailoring Screening Mammography

Research by Trentham-Dietz et al published in the Annals of Internal Medicine recommends that frequency of screening for breast cancer should be based on well-recognized risk factors.

The researchers who were breast-cancer epidemiologists and cancer modelers combined data-collection and conducted simulation modeling using national data for incidence, breast density, and screening performance.

It is an accepted fact that screening benefits and overdiagnosis increase with breast density and relative risk (RR) while false-positive mammograms and benign results on biopsy decrease with increasing risk.

Among women with fatty breasts and an RR of 1.0 or 1.3, breast cancer deaths averted were similar for triennial versus biennial screening for both age groups (50 to 74 years, median of 3.4 to 5.1 vs. 4.1 to 6.5 deaths averted; 65 to 74 years, median of 1.5 to 2.1 vs. 1.8 to 2.6 deaths averted).

Breast cancer deaths averted increased with annual versus biennial screening for women aged 50 to 74 years at all levels of breast density and an RR of 4.0, and those aged 65 to 74 years with heterogeneously or extremely dense breasts and an RR of 4.0. However, harms were almost 2-fold higher.

Triennial screening for the average-risk subgroup and annual screening for the highest-risk subgroup cost less than $100 000 per quality-adjusted life year (QALY) gained which is a value for money of medical interventions.

The authors concluded that average-risk women older than 50 without dense breasts should undergo triennial screening while higher-risk women with very dense breasts should receive annual mammograms.  Such frequency and tailoring of screening mammography will maintain a similar or better balance of benefits and harms than average-risk women receiving annual or biennial screening.