Purpose: The optimal radiation (RT) volume for node-positive endometrial cancer is controversial. This study evaluates clinical outcomes in patients with stage IIIC, N1 endometrial cancer who received RT to the pelvis (PV RT) or pelvis plus para-aortic nodes (PV-PAN RT).
Methods: Overall, there were 89 women with stage IIIC endometrial cancer. Of these, 57 women had N1-only disease, forming the study cohort. Clinicopathologic characteristics, recurrence rates, endometrial cancer-specific survival (ECSS), and overall survival (OS) were examined among patients treated with pelvic RT (n=23) compared with pelvic plus para-aortic RT (n=34). Multivariable analysis of ECSS and OS was performed using Cox regression modeling.
Results: Median follow-up was 5.1 years. Adjuvant chemotherapy was used in 51/57 (89%) of N1 cases. Women with N1 disease who received PV-PAN RT compared with PV RT experienced lower recurrence (26% vs. 52%, P=0.06) and higher survival rates (5 y ECSS 81.5% vs. 47.0%, P=0.04 and OS 79.1% vs. 47.0%, P=0.01). On multivariable analysis, RT volume was not significantly associated with OS, whereas chemotherapy was associated with improved ECSS and OS.
Conclusions: RT conferred excellent local control, whereas chemotherapy was associated with improved survival in women with N1 endometrial cancer. Distant relapse remains the most common site of recurrence despite chemotherapy.