Effects of adjuvant tamoxifen on the endometrium in postmenopausal women with breast cancer:: A prospective long-term study using transvaginal ultrasound

Purpose: To study the value of transvaginal ultrasound (TVS) in endometrial screening of postmenopausal breast cancer patients treated with tamoxifen. Patients and Methods: In 247 tamoxifen-treated (20 to 30 mg/d for greater than or equal to 2 years) women and 98 controls, the endometrium was prospectively followed-up by means of NS every 6 months for up to 5 years. Patients with homogeneous endometrium of more than 10-mm thickness were then scanned repeatedly every 3 months. Results: The mean endometrial thickness wets 3.5 +/- 1.1 mm before treatment and increased to ct maximum of 9.2 +/- 5.1 mm after 3 years of tamoxifen application (P < .0001), which was significantly (P < .0001) thicker compared with controls. Fifty-two asymptomatic patients with thickened or morphologically suspect endometrium underwent hysteroscopy and dilatation and curettage (D&C), resulting in four uterine perforations, Histopathologically, atrophy wets found in 38 patients (73.1%), polyps in nine, hyperplasia in four, and endometrial cancer in one case. In 20 screened patients who reported vaginal bleeding, five atrophies (25%), five polyps, four hyperplasias, and two endometrial cancers were found. Before hysteroscopy and D&C were performed, 30 (69.2%) of 52 asymptomatic and four (20%) of 20 symptomatic patients were scanned by repeated TVS over 2 to 30 months. Invasive diagnostic procedures were significantly (P < .05) more frequent in younger and obese patients. In the controls, one asymptomatic polyp and one symptomatic hyperplasia were found. Conclusion: In tamoxifen-treated patients, TVS offered a high false-positive rate, even with a cutoff value of 10 mm for endometrial thickness and repeated TVS scans. Increased iatrogenic morbidity and only one asymptomatic endometrial carcinoma do not warrant endometrial screening by NS in tamoxifen-treated patients. (C) 2000 by American Society of Clinical Oncology.