Mammographic Density as a Marker of Breast Cancer Risk?

Mammographic density is a strong, independent risk factor for breast cancer. Women with high mammographic density have a fourfold increased risk for breast cancer compared with women with low density. Because age and obesity are the strongest predictors of mammographic density, it is important to adjust for them in risk analyses. In randomized trials, tamoxifen decreased risk for breast cancer and also decreased mammographic density. Combined estrogen plus progestin therapy increased mammographic density. Density is a strong risk factor in low-risk groups (Asian women) and high-risk groups (BRCA mutation carriers). Several risk assessment tools now incorporate mammographic density, including an updated Gail model, though these models require additional validation before they should be used widely. Improvements in density measurements may allow risk assessment to occur routinely with mammography and improve targeting of breast cancer prevention efforts.