Toxicity and Efficacy Following Adjuvant Vaginal Brachytherapy Using 30 Gy in 6 fractions for Stage I and II Endometrial Cancer

Abstract Objective To evaluate outcomes and toxicity in endometrial cancer patients following our institutional adjuvant vaginal cuff brachytherapy (VBT) fractionation scheme. Methods We identified women with FIGO stage I-II endometrial cancer who underwent surgical staging and adjuvant high-dose rate VBT without external beam radiation. All patients received 30 Gy in 6 fractions to the upper one third of the vagina, prescribed to a depth of 5 mm and delivered twice weekly. Toxicities were prospectively elicited at each follow up, and rates of recurrence and survival were retrospectively assessed. Results We identified 247 eligible patients treated from 1992-2018 with a median follow-up of 5.8 years (0.1-24.7 years). Most had stage I disease (52% IA, 37% IB), while 11% were stage II. Deep myometrial invasion was predictive of local recurrence (p=0.002). Five-year rates of local recurrence, regional recurrence, and distant metastases were 5%, 5%, and 7%, respectively. Five-year overall and disease-free survival were 91% and 83%, respectively. The most common grade 1 toxicities were acute fatigue (11% crude rate) and urinary frequency (11%) and chronic (> 6 months) urinary frequency (13%), urinary incontinence (13%), and vaginal stenosis (21%). There were few grade 2 toxicities (all Conclusion The adjuvant VBT fractionation scheme of 30 Gy in 6 fractions results in low rates of toxicity, with no grade 3 or higher adverse events, and local control rates comparable to those from other published series utilizing different fractionation schemes.