To determine the relation of mammographic densities to subsequent breast cancer risk, a case-control study was undertaken using prediagnostic mammograms of screening program participants. Mammograms of cases (n = 266) and controls (n = 301) were blindly assessed for mammographic densities, which were measured by planimetry. The odds of breast cancer increased steadily with increasing breast density (test for trend, P < 0.0001). Breast cancer odds was 1.7 for densities between 5% and 24.9%, 2.5 for 25% through 44.9%, 3.8 for 45% through 64%, and 4.3 for densities of 65% and greater (referent = 4% densities). Odds ratios also increased with increasing densities among women with the P2 and DY mammographic patterns. These findings suggest that the percentage of mammographic densities in the breast can predict breast cancer risk more accurately than a qualitative assessment of mammographic patterns. Cancer 672833-2838,1991.
N MAMMOGRAPHY, normal cancer-free breast tissue 0 represents a continuum of breast types ranging from fatty breasts with no measurable mammographic densities to those displaying extensive regions of density. Mammographic densities are areas of breast tissue seen radiographically over and above that of fat. The densities are composed of epithelial and connective tissue, the type of tissue from which most breast neoplasms develop.
To determine whether the extent of mammographic densities is associated with risk of breast cancer, Wolfe et From the