Low dose adjuvant cylinder brachytherapy for endometrioid endometrial cancer: Vaginal brachytherapy for endometrial cancer

Abstract Purpose To evaluate outcomes and sites of failure for women with early stage endometrial adenocarcinoma treated with adjuvant high-dose-date (HDR) vaginal brachytherapy (VB) with a low dose scheme. Materials and Methods Retrospective review identified 318 patients with FIGO stage I-II endometrioid endometrial cancer who received adjuvant HDR VB to a dose of 24 Gy in 6 fractions from 2005-2017. Patients with Results Median follow-up was 42 months for 243 patients. The 3-year rates of VR, PNR, DM, RFS and OS were 1.9%, 1.5%, 4.3%, 94.1% and 98.9%, respectively. The 3-year VR rates by GOG-99 risk groups were 0%, 1.4% and 3.2% for LR, LIR, and HIR disease (p=0.5). By PORTEC risk stratification, 3-year VR rate was 1.3% for HIR disease. On review of pre-treatment CT images of 6 patients with VR, 3 patients had relapse at the introitus outside the treated vaginal length, and 3 had in-field recurrence at the vaginal apex. Higher BMI was associated with VR, with a 14% increase in risk per BMI unit (kg/m2, p=0.02). There were no reported grade 2 GI or any grade 3 toxicities. Conclusions Adjuvant HDR VB with a low dose regimen results in excellent clinical outcomes for patients with early stage endometrioid endometrial cancer. Patients with higher BMI may be at increased risk of VR, and additional study is needed to optimize brachytherapy treatment parameters.