Adjuvant electronic brachytherapy for early-stage endometrial cancer: clinical outcomes, toxicity, and long-term local control.

PURPOSE: Electronic brachytherapy (eBT) is an emerging alternative to conventional Ir-192 HDR brachytherapy for adjuvant vaginal cuff irradiation. We evaluated long-term clinical outcomes, dosimetric parameters, and treatment-related toxicity in patients with early-stage endometrial cancer treated with adjuvant eBT. METHODS: This single-center retrospective study included 98 patients with early-stage endometrial cancer selected for adjuvant vaginal eBT between 2015 and 2019. Standard fractionation schedules were used. Dosimetric parameters, and acute and late toxicity graded according to CTCAE v5.0 were analyzed. Survival outcomes were assessed using Kaplan-Meier methodology. The median follow-up was 82.5 months. RESULTS: Adequate target coverage was achieved with a median D90 of 92.5% and median V100 of 80.5%. Mean cumulative D2cc doses were 13.3 Gy for bladder, 16.2 Gy for rectum, and 12.2 Gy for sigmoid colon. Acute toxicity was predominantly grade 1-2, with no grade ≥3 events. Grade 3 late toxicity occurred in three patients (3.1%). Vaginal cuff recurrence was observed in 3 patients (3.1%), resulting in a 7-year actuarial local control rate of 96.9%. Seven-year cancer-specific survival and overall survival were 94% and 85.7%, respectively. CONCLUSIONS: Adjuvant electronic brachytherapy provides favorable long-term local control with acceptable toxicity in selected patients with early-stage endometrial cancer. These findings support the feasibility of eBT for adjuvant vaginal cuff irradiation in appropriately selected clinical settings, although prospective comparative studies are needed to establish its role relative to conventional HDR brachytherapy.