Pathology of preinvasive and excellent-prognosis breast cancer.

This review of developments in breast cancer is targeted at two broad areas: 1) indicators of increased risk of sufficient magnitude to attain clinical significance (including precursors) and 2) indicators of good prognosis in invasive breast cancer. A specific and important group that appears in a somewhat intermediate position is the carcinomas in situ, particularly those of the ductal type. This area has attained great importance because of its continually increasing incidence in North America and elsewhere where mammography is used extensively. In addition to discussing in general the advancing subspeciation of these premalignant and low-malignant conditions, we also discuss advances in diagnostic techniques. This specifically relates to the great increase in the utilization of core needle biopsies under mammographic and ultrasonographic guidance.