Endometrial histopathology in 700 patients treated with tamoxifen for breast cancer

Objective. The aim of this study was the evaluation of endometrial histopat hologic findings from 700 patients treated with tamoxifen (Tx) for breast c ancer from two medical centers (United States and France). Methods. A retrospective review of data including histologic slides from 13 4 hysterectomies and 566 endometrial biopsies from Tx-treated patients who presented with abnormal vaginal bleeding and/or abnormal sonograms was perf ormed. Analysis of histologic characteristics included inactive/atrophic an d functional endometria, endometrial polyps, hyperplasia and metaplasia, an d endometrial cancer. Duration of Tx therapy was recorded when available, a nd its correlation with endometrial pathology was assessed. Results. The only statistically significant difference between the data fro m the United States and France was the number of hysterectomies, which was almost double in France (27% vs 13.7%). Nonpathologic endometria made up 61 .14% (inactive/atrophic 46%, functional 15.14%). Pathologic changes were fo und in 39.86% cases, of which polyps were 23.14%, glandular hyperplasia 8%, and metaplasia 3%; endometrial cancer made up 4.71% (33 cases). Nine cance rs were well-differentiated endometrioid adenocarcinomas, and 24 were moder ately or poorly differentiated, of which 13 had nonendometrioid components (serous, clear cell, MMMT). Fifteen cancers were found in endometrial polyp s; 12 were invasive to the myometrium and 4 to blood vessels. The weight of the uteri exceeded 300 g in 15 cases, with 4 exceeding 900 g. The average age of all patients was 60.91 years and of the cancer patients alone it was 69.26 years. The shortest average duration of Tx therapy (2.5 years) was f ound in patients with inactive/atrophic endometria and the longest (6.8 yea rs) in patients with endometrial cancer. Patients with endometrial polyps a nd cancer presented more often with abnormal vaginal bleeding than those wi th inactive/atrophic endometrium. Conclusions. Most Tx-treated patients had no pathologic endometrial changes . Endometrial polyps, hyperplasia, and metaplasia, consistent with an estro gen-agonist effect of Tx, were found in roughly one-third of all patients. The endometrial cancers were often high-grade and invasive rumors. Patients with endometrial pathology were more often symptomatic than patients with inactive/atrophic endometria. (C) 2000 Academic Press.