Study objective: To evaluate the effect of tamoxifen on the endometrium.
Design: Prospective study.
Setting: Department of Obstetrics and Gynecology of the University of Rome.
Patients: One hundred one postmenopausal women with breast cancer receiving tamoxifen 20 to 30 mg/day for at least 1 year; of these 78 were asymptomatic and 23 had vaginal bleeding.
Interventions: All patients underwent transvaginal color Doppler sonography. Those with endometrial thickness greater than 5 mm were advised to undergo hysteroscopy and if necessary endometrial biopsy. For women with endometrial thickness less than 5 mm, hysteroscopy was recommended only if irregular endometrial echotexture was observed.
Measurements and main results: Eleven (14%) asymptomatic patients and 1 (4.3%) with vaginal bleeding had endometrial thickness less than 5 mm (p = 0.4, NS). Women with vaginal bleeding had a significantly thicker endometrium than asymptomatic patients (15.8 +/- 7.5 vs 11.1 +/- 5.7 mm, p = 0.003). In the asymptomatic group 31 polyps, 15 atrophic endometria, and 6 hyperplasias were observed. Two endometrial cancers, 13 polyps, and 3 hyperplasias were detected in patients with vaginal bleeding. Hysteroscopy did not always allow endometrial biopsy, even in the presence of increased endometrial thickness with or without irregular surface. No statistical differences were found for mean pulsatility and resistance indexes of uterine and endometrial arteries between symptomatic and asymptomatic women, but these indexes were significantly lower compared with normal postmenopausal values.
Conclusion: Women receiving tamoxifen, especially those who are asymptomatic, should be closely monitored by transvaginal sonography and hysteroscopy to detect endometrial pathologies.