To determine if there is an advantage to combination chemotherapy and radiation for optimally resected stage IIIC endometrial cancer (EC).

A multicenter retrospective analysis of patients with EC from 1991 to 2008 was conducted. Inclusion criteria were lymph node assessment and optimally resected disease. Recurrence-free (RFS) and overall survival (OS) were analyzed using Kaplan-Meier method and Cox proportional hazards model.

265 patients with optimally resected stage IIIC EC were identified. Postoperative therapies included radiotherapy in 17% (n=45), chemotherapy in 17% (n=46), and both chemotherapy and radiation in 61% (n=161). Three-year RFS was 56% for chemotherapy alone, compared to 73% for radiation alone, and 73% for combination therapy (p=0.12). Those receiving chemotherapy alone had the worst 3-year OS (78%) compared to either radiotherapy alone (95%) or combination therapy (90%) (p=0.005). After adjustment for stage and grade those treated with chemotherapy alone were at a 2.2 fold increased risk of recurrence (95% CI, 1.2 to 4.2; p=0.02) and 4.0 fold increased risk of death (95% CI, 1.6 to 10.0; p=0.004) compared to those treated with chemotherapy and radiation. In contrast there was no significant difference in RFS [HR=1.0 (95% CI, 0.5 to 2.0; p=0.92)] or OS [HR=1.1 (95% CI, 0.3 to 3.6; p=0.91)] for those treated with radiation alone compared to those treated with chemotherapy and radiation.

Adjuvant therapy with either radiation alone or chemotherapy and radiation was associated with improved outcomes for patients with optimally resected stage IIIC EC compared to those treated with chemotherapy only.