Hypofractionated Radiotherapy for Patients with Early-Stage Glottic Cancer: Patterns of Care and Survival

Abstract

Radiotherapy alone is often used to treat early-stage glottic cancer (ESGC); however, the optimal radiation treatment schedule remains unknown. The National Comprehensive Cancer Network (NCCN) guidelines recommend both hypofractionated radiotherapy (HFX) and conventionally fractionated radiotherapy (CFX). We compared overall survival (OS) and treatment patterns among patients treated with HFX vs CFX for ESGC using a large national database. We identified patients diagnosed with stage I-II (cT1-2N0M0) glottic cancer from 2004 to 2013 within the National Cancer Data Base who were treated with either HFX (2.25 Gy/fraction to 63-65.25 Gy) or CFX (2.0 Gy/fraction to 66-70 Gy). The overall survival of patients receiving HFX vs CFX was compared using the log-rank test, multivariable Cox proportional hazards regression, and propensity score matching. All statistical tests were two-sided. Among 10 212 included patients, 4030 patients (39.5%) received HFX and 6182 patients (60.5%) received CFX. Predictors for receipt of HFX included clinical T1 disease, recent year of diagnosis, and treatment at academic and higher-volume centers (all P < .001). Patients treated with HFX increased from 22.1% in 2004 to 58.0% in 2013. HFX was associated with improved OS compared with CFX on univariate (five-year OS = 77.1%, 95% CI = 75.2% to 78.8%, vs 73.5%, 95% CI = 72.1% to 74.8%, respectively, log-rank P < .001) and multivariable analysis (HR = 0.89, 95% CI = 0.81 to 0.98, P = .02), a finding confirmed on propensity score matching. HFX is associated with improved survival compared with CFX among patients treated with definitive radiotherapy for ESGC, particularly among patients with cT2 disease. HFX utilization increased over the study period; however, 40% of patients in our cohort did not receive HFX in the most recent year of our analysis.