Gynaecologic effects of tamoxifen.

Tamoxifen, an estrogen antagonist, is widely used as adjuvant therapy in patients with breast cancer. Its efficacy in increasing survival and reducing recurrence rates has been demonstrated in several European and American studies. However, its effects appear to be tissue specific. Tamoxifen exerts an estrogen effect (agonist) on the endometrium, myometrium and vagina. An increase in uterine cancer has been confirmed in several placebo-controlled clinical trials. Due to the widespread use of this drug, it is timely to review the gynecologic effects of tamoxifen.