Effects of tamoxifen on the human female genital tract: review of the literature

Tamoxifen is a non-steroidal triphenylethylene derivate, with clear antioestrogenic effects on the breast, that is orally administrated for the treatment of breast cancer and its prevention in a high-risk population. This article analyzes the effects of tamoxifen on the adult human female genital tract and considers its carcinogenicity in the gynaecological reproductive organs. It has been found that tamoxifen causes oestrogenic changes of the vaginal and cervical squammous epithelium and increases the incidence of cervical and endometrial polyps. The action of tamoxifen on the human endometrium in postmenopausal women is connected with simple oestrogenic effects including hyperplasia, while in others with endometrial cystic atrophy. In cases where tamoxifen induces endometrial polyps and hyperplasia, the extensive fibrosis accounts for difficulties in obtaining endometrial biopsy or resecting the polyps. In premenopausal patients tamoxifen disrupts the menstrual cycles and causes ovarian cysts, while in postmenopausal patients it induces ovarian cystic tumors and endometriomas. Also, postmenopausal patients treated with tamoxifen may develop endometriosis, adenomyosis and leiomyomata. In addition, randomized trials have shown a link between tamoxifen use in breast cancer patients and the development of endometrial carcinomas. Moreover, of note is the fact that the association of tamoxifen therapy with uterine mesenchymal neoplasms is higher than expected. In conclusion, the most worrying gynaecological side-effect of tamoxifen is the well-known increased risk of endometrial carcinomas. Women with breast cancer treated with tamoxifen should undergo annual gynaecological examination, but endometrial sampling should be obtained only in the event of endometrial bleeding.