Outcome of High-Risk Stage IC, Grade 3, Compared With Stage I Endometrial Carcinoma Patients: The Postoperative Radiation Therapy in Endometrial Carcinoma Trial

Abstract

Purpose Stage IC, grade 3 endometrial cancer is regarded as a high-risk category. Stage IC, grade 3 patients were not eligible for the randomized Postoperative Radiation Therapy in Endometrial Carcinoma (PORTEC) trial, but were registered and received postoperative radiotherapy. Patients and Methods The PORTEC trial included 715 patients with stage IC, grade 1 or 2, and stage IB, grade 2 or 3 endometrial cancer. Patients were randomly assigned after surgery to receive pelvic radiotherapy (RT) or no further treatment. A total of 104 patients with stage IC, grade 3 endometrial cancer were registered, of whom 99 could be evaluated. Patterns of relapse and survival were compared with PORTEC patients receiving RT. Median follow-up was 83 months. Results The actuarial 5-year rates of locoregional relapse were 1% to 3% for PORTEC patients who received RT, compared with 14% for stage IC, grade 3 patients. Five-year distant metastases rates were 3% to 8% for grade 1 and 2 tumors; 20% for stage IB, grade 3 tumors; and 31% for stage IC, grade 3 tumors. Overall survival rates were 83% to 85% for grades 1 and 2; 74% for stage IB, grade 3; and 58% for stage IC, grade 3 patients (P < .001). In multivariate analysis grade 3 was the most important adverse prognostic factor for relapse and death as a result of endometrial cancer (hazard ratios, 5.4 and 5.5; P < .0001). Conclusion Patients with stage IC, grade 3 endometrial carcinoma are at high risk of early distant spread and endometrial carcinoma-related death. Novel strategies for adjuvant therapy should be explored to improve survival for this patient group.