The role of adjuvant radiotherapy in carcinoma of the endometrium - Results in 550 patients with pathologic stage I disease

Objectives. A retrospective analysis of 550 women with pathological stage I carcinoma of the endometrium who were seen between January 1984 and December 1988 was performed in order to assess the value of adjuvant radiation therapy. Methods. Two-hundred twenty-eight patients were treated with surgery alone (S); 97 received adjuvant external beam radiotherapy (S + EXT); 217 received external beam radiotherapy and colpostats (S + EXT + IC); and 8 patients received only colpostats (S + IC), Pelvic radiation therapy, usually 40 Gy in 20 fractions, was administered to 94% of patients whose tumors showed greater than 50% myometrial invasion and to 89% of patients with FIGO grade 3 tumors. Colpostats were used in 40% of patients, the majority of whom had lower uterine segment involvement. Results, The overall survival rate for the whole group using Kaplan-Meier estimates was 84% at 5 years, The 5-year overall survival rates for each treatment group, excluding the 5 + IC group, were 90% for S alone, 79% for 8 + EXT, and 82% for S + EXT + IC. The 5-year disease-free survival rates were 84, 77, and 77%, respectively. Local control rates at 5 years were 93, 94, and 95% in the three treatment groups, but the patterns of relapse were different. Distant metastases occurred more frequently among the patients who received adjuvant radiation therapy (36/49, 73%) than among those who did not (4/19, 21%). Late toxicity was documented in 66 patients. Twelve patients had EORTC/RTOG grade 3 and 4 complications; all had been treated with S + EXT + IC, FIGO grade (P = 0.009), lower uterine segment involvement (P = 0.009), and age (P = 0.03) were significant predictors of worse disease-free survival in a multiple regression analysis. Conclusions. The addition of vaginal vault brachytherapy to external beam radiotherapy did not appear to improve local cure rates nor survival, but increased the incidence of late radiation toxicity. (C) 1998 Academic Press.