Ovarian histopathology in breast cancer patients receiving tamoxifen

Objective. The purpose of this study was to examine ovarian histopathology in tamoxifen-treated breast cancer patients undergoing oophorectomy. Methods. We reviewed the records and ovarian histopathology of 152 breast c ancer patients who underwent oophorectomy at a single institution between J anuary 1980 and October 1996. At the time of oophorectomy, 99 patients had never received tamoxifen, 44 patients were currently receiving tamoxifen, a nd 99 patients had previously received tamoxifen. Patient demographic and m edical data and indication for oophorectomy were examined. Ovarian histopat hology was classified as normal, functional ovarian cyst, benign ovarian tu mor, endometriosis, ovarian cancer, and metastatic cancer. Results. Patient characteristics and indication for oophorectomy did not di ffer significantly based on tamoxifen exposure. There was no difference in the occurrence of benign ovarian tumors, functional ovarian cysts, or metas tatic breast cancer based on tamoxifen exposure. Tamoxifen-treated patients were less likely to have ovarian cancer, 0 of 53 patients (95% confidence interval (CI): 0.0%, 6.7%) compared with 10 of 99 patients (95% CI: 5.0%, 1 7.8%) patients not receiving tamoxifen (P = 0.015). Endometriosis was sligh tly more common in patients currently receiving tamoxifen, but the differen ce was not statistically significant. Conclusions. In women undergoing oophorectomy, there was no evidence that t amoxifen exposure was associated with an increase in benign or malignant pr imary or metastatic ovarian neoplasm or in functional ovarian cysts. Furthe r study is necessary to better define any association between tamoxifen and endometriosis and the effect of tamoxifen on ovarian cancer risk. (C) 1999 Academic Press.