Primary Radiotherapy Versus Surgery in Early-Stage Endometrial Cancer Among High-Risk Surgical Patients: A Retrospective Comparative Study.

Background/Objectives: Surgery is the standard treatment for early-stage endometrial cancer (EC); however, some patients are medically inoperable due to comorbidities or morbid obesity. Definitive image-guided brachytherapy (BT) with or without external beam radiotherapy (EBRT) is a curative alternative, although comparative data with surgery remains limited. This study compared cancer-specific survival (CSS) at 2 and 5 years in high-risk surgical patients with early-stage EC (FIGO 2009 I-II), treated with definitive radiotherapy or surgery. Secondary endpoints included overall survival (OS), recurrence-free survival (RFS), disease-free survival (DFS), and toxicity. Methods: Retrospective comparative study including 72 patients treated between 2011 and 2023: 36 medically inoperable treated with BT +/- EBRT and 36 matched undergoing surgery. Survival outcomes were estimated using Kaplan-Meier methods and compared using log-rank tests. Results: Median age was 74 years and mean BMI was 38.1 kg/m2; 75% were morbidly obese, with endometrioid carcinoma being the predominant histology (88.9%). Five-year CSS was 97.2% in the radiotherapy group versus 91.7% in the surgery group (p = 0.39). Five-year RFS was identical in both groups (86.1%), with recurrence rates of 13.9%. Five-year OS was lower in the radiotherapy group (66.7% vs. 77.8%; p = 0.3), without statistical significance. Grade ≥3 radiotherapy-related toxicity occurred in 19.4%, whereas severe surgical complications occurred in 8.3%. Conclusions: Definitive BT ± EBRT is an effective and well-tolerated curative option for medically inoperable early-stage EC, with survival and recurrence outcomes comparable to surgery, supporting its role as a valid therapeutic alternative in high-risk surgical patients.