Mammographic patterns and risk of breast cancer.

A study of 171 breast cancer cases matched by age and race to asymptomatic controls was undertaken to check Wolfe's assertion [1, 2] that breast cancer risk depends strongly on the mammographic classifications N1, P1, P2, and DY. The classifications were made blindly relative to all variables, including the case-control factor. Distribution of the four categories among the breast cancer patients in this study was consistent with the distribution found by Wolfe. (P = .46). Our age-standardized risk ratio estimates of the categories, relative to N1, are 1.5 for P1, 2.7 for P2, and 7.2 for DY. While not as striking as Wolfe's estimates, the same monotone trend is evident, and the cases and controls differ significantly with respect to the distributions of the four categories (P less than .01).