Practice patterns and survival in FIGO 2009 stage 3B endometrial cancer

Objective: To describe the practice patterns and outcomes of patients with stage 3B endometrial cancer. Methods: We queried the National Cancer Database for all surgically staged, stage 3 patients between 2012 and 2016. Patients who received any pre-operative therapy were excluded. Demographics, tumor factors, and adjuvant therapy for the stage 3 substages were compared. Logistic regression was used to identify factors associated with adjuvant therapy. Kaplan Meier curves were generated and compared using the log-rank test. Multivariable Cox Proportional Hazards Model was used to adjust for prognostic factors. Findings with p < 0.05 were considered significant. Results: Of 7363 patients with stage 3 disease, 478 (6%) had stage 3B; 1732 (23%) had stage 3A, 3457 (48%) had stage 3C1, and 1696 (23%) had stage 3C2 disease. Post-surgical treatment consisted of: combined chemotherapy (CT) and radiation (RT) (49%), CT alone (28%), RT alone (9%), 14% received no postoperative therapy. Among all stage 3 substages, patients with stage 3B disease were the least likely to receive any CT, and the most likely to receive RT alone. After adjusting for known prognostic factors, patients with stage 3A (Hazard ratio (HR) of death = 0.64) and 3C1 (HR of death = 0.79) disease had significantly worse overall survival compared to stage 3B; survival was not demonstrably different from patients with stage 3C2 disease. Patients with stage 3B disease who received CT + RT had the best overall survival. Conclusion: Survival of patients with stage 3B disease is similar to that of patients with para-aortic node metastases and is inferior to all others with stage 3 endometrial cancer. Less frequent CT and a higher rate of post-operative RT alone, describes a distinct practice from that seen in other stage 3 patients.