Tamoxifen (TAM) is the endocrine treatment of choice in the first-line therapy for all stages of breast cancer, in both pre- and postmenopausal women. Some clinical studies indicated a small but significant increase in the risk of subsequent endometrial carcinoma in breast cancer women who take TAM as an adjuvant therapy. In this study, we present two cases of breast cancer patients in whom endometrial cancer was diagnosed during TAM treatment; the current status of knowledge on the relationship between TAM use and the risk of endometrial cancer is reviewed.
key words: tamoxifen • breast cancer • endometrial cancer

Keywords: endometrial cancer, breast cancer, tamoxifen