Little information is available concerning the influence of specific extrauterine sites in patients with stage m endometrial carcinoma. To define better the prognostic factors and patterns of failure, we reviewed 105 patients with pathologic stage HI disease (1988 FIGO system) who were treated between 1970 and 1990. Following hysterectomy, all patients received postoperative external beam irradiation to the pelvis alone (88 patients) or to the pelvis and paraaortic regions (1 7 patients) for pathologically positive paraaortic nodes. Actuarial techniques were used to analyze survival and recurrences. Range of followup was 7-251 months (median 83 months). Five-year disease-free survival (DFS) for all patients was 64%. Multivariate analysis revealed clear celYpapillary serous histology and histologic grade to be significant predictors of DFS. Based on our analysis, four prognostic groups are described for the purpose of predicting outcome and patterns of disease recurrence. Patients who have a single extrauterine site of involvement and histologic grade 1 tumors have an excellent prognosis. Patients with a single extrauterine site of involvement and grade 2 or 3 tumors have a lower DFS rate, as do patients with two or more sites of extrauterine involvement. However, patterns of disease recurrence for these groups are different, and these are discussed.