High Incidence of Carcinosarcoma among Patients Previously Treated with Tamoxifen.

BACKGROUND: Tamoxifen acts as an estrogen antagonist within the breast tissue. In the uterus, tamoxifen is an agonist for some estrogen receptors and therefore can cause hyperplasia or neoplasia in the endometrium.

OBJECTIVES: To compare characteristics of patients with uterine sarcoma who were and were not previously treated with tamoxifen.

METHODS: The medical records of all women with uterine sarcoma who had been treated at the Carmel Medical Center in Haifa, Israel, during 2000-2013 were retrospectively reviewed. Disease characteristics, histological type of sarcoma, patient demographics, treatments and final outcomes were compared between patients who had and those who had not been exposed to tamoxifen.

RESULTS: Of the 66 patients identified, 14 (21%) had been exposed to tamoxifen, one of them for 3 years and 13 for at least 5 years. Mean ages were 69 ± 8 and 66 ± 12 years for those exposed and those not exposed to the drug, respectively. Rates of uterine carcinosarcoma were 86% (12/14) and 44% (23/52), respectively (P < 0.006). Patients with carcinosarcoma were older than other sarcoma patients (73 ± 7 vs. 59 ± 11 P < 0.005).There were no statistically significant differences between the two groups in rates of diabetes mellitus, hypertension, dyslipidemia or heart disease. The mean time from diagnosis to death was 7.37 ± 0.42 years. The overall survival rates of carcinosarcoma patients were not statistically different from that of other sarcoma patients. Tamoxifen exposure was not associated with overall survival among all sarcoma patients, nor among the subgroup of carcinosarcoma patients.

CONCLUSIONS: Tamoxifen treatment was associated with elevated incidence of carcinosarcoma among women with uterine sarcoma, but was not found to be associated with prognosis or with co-morbidities.