Which prognostic factors influence the outcome of patients with surgically staged endometrial cancer treated with adjuvant radiation?

Purpose: Despite the fact that retrospective reviews have documented pelvic failure rates ranging from 15-20% in patients with high-risk uterine-confined endometrial cancer who have received no or 'inadequate' RT, the role of RT has been questioned. We sought to analyze pelvic control and disease-free survival for a large data base of women with corpus cancers managed with initial surgery followed by adjuvant irradiation. Methods and Materials: Between 1983 and 1993, 294 patients received adjuvant postoperative RT from one of three academic radiation practices. RT consisted of vaginal brachytherapy alone in 28 patients, pelvic RT in 173 patients, pelvic RT with vaginal brachytherapy in 97 patients, and whole abdominal RT in 2 patients. Lymph nodes were evaluated in 49%. The median number of pelvic and periaortic LN in the pathology specimen were 6 and 4, respectively. Median follow up was 63 months. Results: 5-year disease-free survival (DFS) rate and pelvic control rates were 86 and 95%, respectively. Patient-related, treatment-related, and tumor-related characteristics were assessed for the effect on time to relapse. Unfavorable histology, older age, and capillary space invasion were univariately associated with decreased DFS and pelvic control. Pathologic Stage II patients had significantly worse DFS than Stage I patients. Multivariate analysis revealed that age, capillary space invasion, and histology were jointly predictive of disease free survival. Conclusion: The excellent pelvic control and disease-free survival of patients with uterine-confined disease in this series suggest that adjuvant RT should continue for patients with high risk disease. This analysis of a large group of postoperatively treated patients will provide a basis for determining alternative treatment strategies for patients who have an increased risk of disease recurrence despite RT