MRI-guided brachytherapy for vaginal recurrence of endometrial cancer

Vaginal recurrence of endometrial cancer can be salvaged by external beam radiotherapy and vaginal brachytherapy, but data on MRI-guided brachytherapy is limited. This study evaluated disease and toxicity outcomes of patients treated with MRI-guided brachytherapy for vaginal recurrence of endometrial cancer.

Patients who received salvage MRI-guided interstitial/intracavitary brachytherapy for vaginal recurrence of endometrial cancer between 2015 and 2023 were retrospectively reviewed. Local failure (LF) was estimated using the cumulative incidence function. Disease-free (DFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Toxicities were assessed using the Common Terminology Criteria for Adverse Events (version 5).

Of the 56 patients, 17 (30%) and 39 (70%) were treated with intracavitary (multichannel vaginal applicator) and interstitial (Syed-Neblett template) brachytherapy, respectively. Fifty-three (94%) had endometroid adenocarcinoma histology. The median high-risk clinical target volume D_90% was 82 Gy. With a median follow up of 39.5 months, 11 patients (20%) developed recurrence: four local failures (LFs), three regional failures, and seven distant failures (simultaneous failures at different sites included). The 2-year LF was 5.9% (95% confidence interval [CI] 1.5%-15.9%); 2-year DFS was 83% (95% CI 73%-94%); and 2-year OS was 94% (95% CI 87%-100%). There were few late toxicities, with the highest toxicity grade being grade 2: 0 gastrointestinal, one genitourinary and six vaginal.

Patients with vaginal recurrence of endometrial cancer treated with MRI-guided interstitial/intracavitary brachytherapy had favorable local control, DFS, OS and toxicity rates.