PROGNOSTIC-SIGNIFICANCE OF BENIGN PROLIFERATIVE BREAST DISEASE

Background. Recent studies concerning an association between benign br east diseases and risk of subsequent breast cancer have focused on ben ign proliferative lesions recognized in biopsy specimens. Some have im plicated atypical hyperplasia as being associated with the greatest ri sk. Methods. The histologic sections of specified benign breast lesion s from 1799 women were reviewed and reclassified, using published crit eria for proliferative disease. Prognostic significance was assessed b y relating the pathologic findings to the development of breast cancer observed during an average 21 years of follow-up, in which time 157 w omen developed the disease. Results. Benign proliferative changes were recognized in 85% of the patients, with a corresponding relative risk of subsequent carcinoma equal to 2.2 times population rates (95% conf idence limits, 1.9 and 2.6). Increasing levels of hyperplasia and atyp ia in lobules or ducts were associated with modest increases in risk, ranging from 2.1 to 2.3 to 3.0 for proliferative changes with no atypi a, mild atypia, and moderate to severe atypia, respectively. This tren d was not statistically significant. The most significant risk indicat ors in this study were the presence of adenosis (relative risk, 3.7), and moderate or severe atypia in ducts (relative risk, 3.9). Conclusio ns. Benign proliferative breast disease recognized in biopsy specimens is associated with an increased risk of future breast cancer, but fin e distinctions among levels of hyperplasia and atypia did not signific antly distinguish risk among patients in this study.