COMPARISON OF ENDOMETRIAL CHANGES AMONG SYMPTOMATIC TAMOXIFEN-TREATEDAND NONTREATED PREMENOPAUSAL AND POSTMENOPAUSAL BREAST-CANCER PATIENTS

Breast cancer patients who received tamoxifen as adjuvant therapy have been reported to have more endometrial lesions such as polyps, hyperp lasia, or carcinoma. We conducted a prospective study to elucidate the endometrial changes of premenopausal and postmenopausal breast cancer patients with tamoxifen. Sixty-seven symptomatic breast cancer patien ts who had been on tamoxifen treatment, including 34 premenopausal and 33 postmenopausal patients, and another group of 48 patients who had not been on tamoxifen, including 25 premenopausal and 23 postmenopausa l patients, were recruited. Symptomatic patients were defined as havin g hypermenorrhea or abnormal vaginal bleeding among premenopausal pati ents or postmenopausal bleeding among postmenopausal patients. Endomet rial thickness and uterine size determined by vaginal ultrasonography, histologic findings, and risk factors for endometrial cancer were com pared. The mean endometrial thickness and uterine size showed no stati stically significant difference in premenopausal patients with (n = 34 ) or without (n = 25) tamoxifen treatment, whereas there was a signifi cant difference in the postmenopausal patients with (n = 33) or withou t (n = 23) tamoxifen treatment (12.11 +/- 12.38 mm vs 5.41 +/- 2.70 mm , P = 0.025; 234.71 +/- 76.36 cm(3) vs 108.81 +/- 81.27 cm(3), P = 0.0 018, respectively). The frequency of endometrial histopathologic findi ngs was 23.5% (8/34) in tamoxifen-treated women compared with 12.0% (3 /25) in nontreated women (P = 0.269) in the premenopausal groups. In c ontrast, it was remarkably high with 66.7% (22/33) in tamoxifen-treate d women compared with 30.4% (7/23) in the nontreated women in the post menopausal groups (P = 0.025). There were four postmenopausal patients with tamoxifen, including three with atypical endometrial hyperplasia and one endometrial carcinoma, in contrast to no postmenopausal nontr eated patients, although this difference did not reach statistical sig nificance in this study (P = 0.096). There was a remarkably high preva lence of endometrial histopathologic findings in symptomatic tamoxifen -treated breast cancer patients, especially postmenopausal women. Tamo xifen might be associated with premalignant or malignant changes in po stmenopausal endometrium. Thus timely, aggressive histologic assessmen t such as curettage or hysteroscope should be performed to detect the endometrial lesions when symptoms occur. Vaginal ultrasonography could be a useful tool to detect the endometrial lesions. (C) 1997 Academic Press.