Having dense breasts (more fibroglandular tissue than fatty tissue, as visualized on a mammogram) reduces the sensitivity of mammography by masking breast cancers and carries a 1.6- to 2.0-fold increased independent risk for breast cancer. To inform women about these risks, 38 U.S. states and the federal government have enacted legislation requiring a written dense breast notification (DBN) of a patient’s breast density after a mammogram, but there still is limited evidence about what breast density means, and what the implications are, to women.
