ACOG committee opinion. No. 336: Tamoxifen and uterine cancer.

Tamoxifen may be associated with endometrial proliferation, hyperplasia, polyp formation, invasive carcinoma, and uterine sarcoma. Any symptoms of endometrial hyperplasia or cancer reported by a postmenopausal woman taking tamoxifen should be evaluated. Premenopausal women treated with tamoxifen have no known increased risk of uterine cancer and as such require no additional monitoring beyond routine gynecologic care. If a typical endometrial hyperplasia develops, appropriate gynecologic management should be instituted, and the use of tamoxifen should be reassessed.