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

Background: 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 hypo-fractionated 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. Methods: 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. Results: 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. Conclusions: 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.