ENDOMETRIAL CHANGES IN POSTMENOPAUSAL BREAST-CANCER PATIENTS RECEIVING TAMOXIFEN

Objective: To assess the estrogenic effect of tamoxifen and associated pathologic changes of the endometrium in postmenopausal breast cancer patients. Methods: The endometrium of 103 gynecologically asymptomati c postmenopausal breast cancer patients was examined. Fifty-one had be en treated with tamoxifen and 52 had not received any hormonal treatme nt. The two groups were similar in age, parity, age at menopause, and body mass index. Results: Compared with the control subjects, the tamo xifen patients had a thicker endometrium (mean +/- standard deviation 10.4 +/- 5.0 versus 4.2 +/- 2.7 mm; P = .0001) and larger uterine volu me (45 +/- 27 versus 25 +/- 11 cm3; p =.001), as determined by transva ginal sonography. Hysteroscopy showed an atrophic endometrium in 28% o f the patients in the tamoxifen group, as compared with 87% of the con trol patients (P = .0001). Endometrial polyps were more frequent in th e tamoxifen group (36 versus 10%; P = .004), which included one patien t with atypical hyperplasia, one with adenomatous hyperplasia, and one with endometrial adenocarcinoma; two controls had endometrial adenoca rcinoma. Conclusion: The results provide evidence for an estrogenic ef fect of long-term tamoxifen treatment on the postmenopausal uterus and show it to be associated with an increased occurrence of polyps.