IV.4 Iatrogenic risks of endometrial carcinoma after treatment for breast cancer in a large French case—Control study

In a case-control study, including 135 cases of endometrial carcinoma diagnosed after breast cancer and 467 controls, the relative risks for endometrial carcinoma were higher for women treated with tamoxifen (4.9; P = 0.0001) and those who undergone pelvic radiotherapy (7; 8; P = 0.0001). After adjusting for confounding factors, a multivariate analysis has shown an increased risk of endometrial carcinoma for tamoxifen users, especially for treatment longer than 3 years and for pelvic radiotherapy. Patients treated with tamoxifen had more advanced tumours and lower survival rates than those who had not received tamoxifen.