Tamoxifen effects on endometrium.

BACKGROUND: To evaluate the effects on the endometrium of a long term treatment with Tamoxifen in postmenopausal patients, asymptomatic for gynecologic disorders, surgically treated for breast cancer. SETTING: Outpatient menopausal clinic and endoscopic unit. PATIENTS AND INTERVENTIONS: 45 patients (Group I) were treated with 20 mg of Tamoxifen daily for a mean of 23.4 months. Seven patients (Group II) represented the control group and did not receive Tamoxifen. A transvaginal ultrasonography and a hysteroscopic guided biopsy were performed in all patients. RESULTS: Sagittal sonograms showed abnormal endometrial thickening (range 8-32 mm, mean 13 mm) in 17 patients (35.4%) of Group I and in 1 patient of Group II. Pathology on endometrial tissue sampling obtained at the time of hysteroscopy showed hyperplastic endometrial polyps in 3 patients (6.25%), endometrial hyperplasia in 16 patients (33.4%), while 1 patient had an endometrial polyp cancer on a background of hyperplasia and 1 had a superficial endometrial cancer (4.1%). Out of the 7 patients of Group II, one had an endometrial polyp, while 6 had no relevant endometrial abnormalities. CONCLUSIONS: Our study confirms that Tamoxifen treatment is associated with an increased incidence of proliferative and neoplastic endometrial changes. No obvious correlation was found between the length of Tamoxifen exposure time and occurrence of endometrial pathologies. It is mandatory to undertake twice per year gynecological evaluations for patients treated with Tamoxifen to promptly identify and correctly manage endometrial changes.