Uterine Malignancy following Tamoxifen Use in Breast Cancer Patients in Iran: Case Series and Literature Review

Background: This study evaluated tumor characteristics and survival in women with breast cancer whosubsequently developed uterine cancer.
Methods: Information about endometrial cancer in tamoxifen usersfollowing breast cancer refered to the gynecologic oncology clinic of Vali-Asr hospital between 1997-2007 wasevaluated.
Results: Among 330 patients with endometrial cancer, 5 were in women previously diagnosed withbreast cancer. Two cancers were malignant mixed Mullerian tumors of the uterus (MMMT), 2 were endometrioidadenocarcinomas, and one was a papillary clear cell carcinoma. Patients received tamoxifen for 4-8 years. Theendometrial cancers occurred 2-11 years after initial treatment for the breast cancers. Four of the endometrialcancers featured abnormal uterine bleeding and one of them had increased vaginal discharge and all werediagnosed on endometrial curetting. All patients received standard surgical staging for endometrial cancer andall except one were stage I. At laparotomy of one patient, an advanced stage MMMT was found with diffusedperitoneal spread and ascites. In spite of the surgery, she died of disease, 3 months later. The other patientsremain recurrence-free for breast cancer and uterine cancer after 6-120 months.
Conclusion: Breast cancerpatients who use tamoxifen and have early stage endometrial cancers demonstrate a good prognosis. Abnormaluterine bleeding or vaginal discharge is the most important symptom.