Tamoxifen and the female reproductive tract

The use of tamoxifen among women with breast cancer or at high risk of the disease has greatly expanded over the past several decades. Tamoxifen has a complex effect on the female reproductive tract and several tamoxifen-associated changes have been described among tamoxifen users. These include endometrial thickening, cervical and endometrial polyps, endometrial hyperplasia, endometrial adenocarcinoma, uterine sarcoma, increase in the size of uterine leiomyomata, exacerbation of endometriosis and ovarian cysts. The most common uterine change associated with tamoxifen is endometrial polyps. The annual incidence of endometrial cancer among women on tamoxifen is 2 per 1000 and seems to be related to the cumulative tamoxifen dose. It is not clear whether endometrial cancer occurring among women on tamoxifen is of worse prognosis than endometrial cancer occurring among women not receiving tamoxifen. Tamoxifen is associated with several sonographic changes which make the use of ultrasound in surveillance of these patients difficult. There is no indication to implement routine screening for endometrial cancer among all women on tamoxifen. However, endometrial biopsy, preferably via hysteroscopy, should be considered in women with uterine bleeding.