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 S + IC group, were 90% for S alone, 79% for S + 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.