Endometrial cancers in postmenopausal breast cancer patients with tamoxifen treatment.

To evaluate possible predicting factors for endometrial cancer in postmenopausal breast cancer patients with tamoxifen treatment, we compared various clinical features between 12 postmenopausal breast cancer tamoxifen-treated patients with endometrial cancer and a control group of 261 otherwise similar patients without this endometrial pathology. These comparisons were based on a long-term prospective follow-up. Several clinical factors such as longer duration of breast disease, older patient age, lower frequency of chemotherapy administration, and higher frequency of postmenopausal bleeding were found among the tamoxifen-treated patients with endometrial cancers, and were significantly different when compared to the control group. Only eight (66.7%) had postmenopausal bleeding, and a preoperative diagnosis of endometrial cancer was made in only six (50.0%). When considering postmenopausal bleeding as a marker for endometrial cancer in the study patients, sensitivity was 67% and specificity was 98%.