Impact of Para-Aortic Lymphadenectomy on Clinically FIGO Stage IIIC1 High-Grade Endometrial Cancer: A Retrospective Cohort Study from Two Tertiary Centers in Korea and Taiwan.

: The therapeutic effect of para-aortic lymphadenectomy in patients with clinically para-aortic node-negative diseases remains controversial. In this study, we investigated whether combined pelvic and para-aortic lymphadenectomy has a survival benefit compared with pelvic lymphadenectomy alone in patients with clinically FIGO stage IIIC1 high-grade endometrial cancer. : We retrospectively reviewed patients with clinically FIGO stage IIIC1 high-grade endometrial cancer in the period between January 2000 and December 2020 at two tertiary centers. The patients were stratified according to type of lymphadenectomy and subgroup analyses performed. Kaplan-Meier analysis and a Cox proportional-hazards model were used to evaluate survival outcomes. : A total of 56 patients were identified. Of these patients, 18 underwent pelvic lymphadenectomy alone and 38 underwent combined pelvic and para-aortic lymphadenectomy. After staging surgery, 34 (60.7%) patients had pathologically confirmed lymph node metastases. Within a median follow-up of 57.5 months, there were no significant differences in recurrence-free survival (RFS) and overall survival (OS) between the two groups. In subgroup analyses, the node- and lymphovascular space invasion (LVSI)-positive patients characterized by grade 3 endometrioid histologic type ( = 0.010) or negative peritoneal washing cytology ( = 0.035) had an RFS benefit from combined pelvic and para-aortic lymphadenectomy. : The addition of para-aortic lymphadenectomy to pelvic lymphadenectomy did not improve survival in patients with clinically FIGO IIIC1 endometrial cancer. However, para-aortic lymphadenectomy may have RFS benefit for patients with grade 3 endometrioid histologic type and positive LVSI.