Tamoxifen and the uterus

Abstract

The effects of tamoxifen on the endometrium have caused concern since the late 1980s,1,2 and clear evidence of endometrial changes has now emerged from three studies in postmenopausal women - one case-control study of breast cancer3 and two randomised controlled trials, one in women with early breast cancer4 and one in healthy women with a family history of the disease.5 In most women treated with tamoxifen the endometrium remains atrophic, but epithelial metaplasia, simple hyperplasia, atypical hyperplasia, endometrial polyps, and endometrial cancers have all been reported in women taking a dose of 20 mg/day.6 There is evidence that local expression of insulinlike growth factor I and insulin-like growth factor binding protein-3 are important in tamoxifen's uterotrophic effect.7 In patients with breast cancer the risk of endometrial changes is justified by the protective effect of tamoxifen against the cancer and against osteoporosis and cardiovascular disease.8 The risk-benefit equations are, however different in healthy postmenopausal women taking tamoxifen for as yet unestablished benefits, and in such women pelvic assessment should not be confined to those who have abnormal …