Re: "Polycystic ovaries and the risk of breast cancer"

Gammon and Thompson (1) recently reported in the Journal the results of an analysis of data from the Center for Disease Control's Cancer and Steroid Hormones Study to examine the association between a history of physician-diagnosed polycystic ovaries and the risk of breast cancer. Despite the small number of exposed cases (n =23) and controls (nm 44), their data strongly support the conclusion that a history of polycystic ovaries protects against premenopausal and carly postmenopausal breast cancer. These results are in apparent conflict with those reported in a previous cohort study by Coulam et al. (2), who found a threefold increase in postmenopausal breast cancer in women with polycystic ovaries. Such discrepancy may reflect real, albeit unexplained differences between premenopausal and postmenopausal women in the influence of endogenous hormones on breast cancer.