To determine the survival outcomes, prognostic factors, and patterns of failure in patients with malignant mixed Müllerian tumor (MMMT) of the uterus.

Between 1954 and 1998, 300 patients with clinical Stage I-III MMMT of the uterus were treated with curative intent at The University of Texas M. D. Anderson Cancer Center. Their hospital records were reviewed to obtain patient and tumor characteristics; details of surgery, radiotherapy (RT), and chemotherapy; and long-term outcome. Surviving patients were followed for a median of 109 months (range 15-138). Survival rates were calculated using the Kaplan-Meier method, with differences assessed by log-rank tests.

Of the 300 patients, 113 (38%) were treated with surgery alone, 160 (53%) with surgery plus adjuvant EBRT or ICRT, and 27 (9%) with RT alone. Forty-eight patients received adjuvant chemotherapy. At 5 years, the overall rates of survival and cause-specific survival were 31% and 33%, respectively. Women who were postmenopausal or had a history of prior pelvic RT, pain at presentation, clinical Stage II-III disease, uterine enlargement (>/=12 weeks), or an abnormal Papanicolaou smear finding had a significantly poorer prognosis than the other patients in the series. Of the 273 patients who underwent surgery, those who had positive abdominal washings, uterine length >10 cm, or extrauterine spread of disease to the cervix, adnexa, or peritoneum had a significantly worse prognosis than the other patients. Factors found on multivariate analysis to have an independent adverse influence on cause-specific survival included postmenopausal status (p = 0.0007, relative risk [RR] 3.3), uterine length >10 cm (p = 0.0001, RR 2.2), cervical involvement (p = 0.002, RR 1.8), and peritoneal involvement (p = 0.0001, RR 4.3). At 5 years, the rates of pelvic and distant disease recurrence for the entire group of 300 patients were 38% and 57%, respectively. The most common site of distant recurrence was the peritoneal cavity. Patients treated with pelvic RT had a lower rate of pelvic recurrence than patients treated with surgery alone (28% vs. 48%, p = 0.0002), but the overall survival rates (36% vs. 27%, p = 0.10) and distant metastasis rates (57% vs. 54%, p = 0.96) were not significantly different. However, patients treated with pelvic RT had a longer mean time to any distant relapse (17.3 vs. 7.0 months, p = 0.001) than patients treated with surgery alone. The use of adjuvant chemotherapy did not correlate with the survival rate or rate of distant metastasis.

Adjuvant pelvic RT decreased the risk of pelvic recurrence and may delay the appearance of distant metastases after hysterectomy for MMMT. However, the survival rates remain poor because of a high rate of distant recurrence. As more effective systemic chemotherapy is developed to control microscopic distant disease, the role of RT in controlling locoregional disease in the pelvis and abdomen may become more important. Future research should consider programs that integrate surgery, RT, and chemotherapy to maximize the probability of cure.