(OA23) Do Vaginal Recurrence Rates Differ Among Common Adjuvant Vaginal Brachytherapy Regimens in Early-Stage Endometrial Cancer?

Abstract Purpose We sought to retrospectively examine clinical outcomes for three adjuvant vaginal high-dose-rate (HDR) brachytherapy regimens after hysterectomy for early-stage endometrial cancer. Methods Included were women of all ages from two independent hospital systems diagnosed with Stage I-II endometrial cancer of any grade between 2000 and 2016 who underwent hysterectomy followed by adjuvant vaginal cylinder HDR brachytherapy with either 7.0 Gy × 3 fractions prescribed to 0.5 cm vaginal depth, 6.5 Gy × 3 fractions prescribed to 0.5 cm vaginal depth, or 6.0 Gy × 5 fractions prescribed to the vaginal surface. Outcomes included vaginal recurrence (VR), pelvic recurrence, distant recurrence, locoregional recurrence, recurrence-free survival, and overall survival. Results Of the 348 women, 45 (13%) received 7.0 Gy × 3 fractions, 259 (74%) received 6.5 Gy × 3 fractions, and 44 (13%) received 6.0 Gy × 5 fractions. Women receiving 5-fraction brachytherapy were more likely to be younger with a higher performance status. At a median follow-up of 4.5 years, VR rates were 2.2%, 0.8%, and 4.5%, respectively. Multivariate analysis revealed no significant differences in the risks for VR among brachytherapy regimens. Risks for VR, pelvic recurrence, distant recurrence, locoregional recurrence, recurrence-free survival, and overall survival did not differ between propensity score–matched five- and 3-fraction brachytherapy cohorts. Conclusions VR rates after hysterectomy and adjuvant vaginal brachytherapy for early-stage endometrial cancer were low and not significantly different by HDR dose fractionation.