CHANGES MIMICKING ENDOMETRIAL NEOPLASIA IN POSTMENOPAUSAL, TAMOXIFEN-TREATED WOMEN WITH BREAST-CANCER - A TRANSVAGINAL DOPPLER STUDY

In menopausal patients with breast cancer who receive tamoxifen therap y, transvaginal sonography may show an abnormal endometrium. Our objec tive was to evaluate the effects of prolonged tamoxifen therapy on end ometrial bloodflow in postmenopausal patients with breast cancer, and to correlate blood flow characteristics with the sonographic appearanc e of the endometrium and its pathology. Tiansvaginal color Doppler ult rasound examinations were performed on 45 postmenopausal women (age ra nge 54-70 years) with breast cancer, who had been treated with tamoxif en for 1-3 years. Twenty women (Group I) had a thick, irregular, cysti c endometrium of greater than or equal to 5mm, and 25 (Group 2) showed a thin endometrium of < 5 mm. The blood flow response was assessed by visualization of arterial waveforms in the endometrial and subendomet rial regions with a transvaginal color flow imaging system. Resistance indexes (RI) were calculated for analysis and correlated with endomet rial appearance and histology. The mean RI in Group I was 0.39 +/- 0.1 0 (range 0.32-0.54), while the mean RI in Group 2 was 0.79 +/- 0.10 (r ange 0.54-0.90; p < 0.001). On histology, 12 patients in Group I showe d atrophic endometria confirmed by hysteroscopy, while in the remainin g eight, endometrial polyps were found. In Group 2, all patients had s canty, atrophic endometria. Six of the eight patients with endometrial polyps had an RI of < 0.4 and none had malignant changes. These data suggest that tamoxifen therapy in women with postmenopausal breast can cer induces endometrial, morphological and blood flow changes, mimicki ng endometrial neoplasia. If low RI (0.4) and an abnormal appearance o f the endometrium had been relied on as criteria that indicate maligna ncy, six of our patients (30%) with thick endometria would have been m isdiagnosed as having carcinoma.