Clinical and dosimetric outcomes of a 3-fraction high-dose-rate brachytherapy boost for the treatment of locally advanced cervical cancer in a safety net hospital.

Purpose: To report outcomes of a 3-fraction HDR brachytherapy boost for the treatment of locally advanced cervical cancer (LACC) at a large safety net hospital.

Methods and materials: A retrospective review of 93 patients with FIGO 2018 Stage IA2 to IVB cervical cancer treated with HDR brachytherapy boost in 3 fractions between 2017 and 2022 was conducted. The 2-year local control (LC), progression-free survival (PFS), and overall survival (OS) was estimated using Kaplan-Meier estimators. Hazard ratios of covariates for local failure (LF) were determined using univariate Cox proportional hazard models.

Results: Median follow-up time was 31 months. Mean cumulative EQD2 of HR-CTV D90 was 85.3 Gy (95% CI 84.2, 86.4). Mean cumulative EQD2 of the D2cc for bladder, rectum, sigmoid, and small bowel was 74.7 Gy (95% CI 72.4, 77.0), 58.2 Gy (95% CI 56.7, 59.6), 60.9 Gy (95% CI 59.4, 62.3), and 58.9 Gy (95% CI 56.7, 61.1) respectively. Two-year LC, PFS, and OS were 80.9% (95% CI 73.1%, 89.5%), 63.2% (95% CI 54.0%, 74.1%), and 85.2% (95% CI 78.1%, 93.0%) respectively. The hazard ratio for LF for incomplete concurrent chemotherapy regimen was 3.07 (95% CI 1.17, 8.09; p = 0.02). Three percent of patients experienced late grade 3+ toxicities after radiation therapy.

Conclusions: Three-fraction HDR brachytherapy boost was generally well-tolerated by patients and may be a viable alternative in the treatment of LACC.