Patterns of Care for Patients With Early-Stage Glottic Cancer Undergoing Definitive Radiation Therapy: A National Cancer Database Analysis.

Abstract

To characterize practice patterns, including temporal trends, in fractionation schedules among patients in the United States undergoing definitive radiation therapy for early-stage glottic cancer and to compare overall survival outcomes between fractionation schedules. We queried the National Cancer Database for patients with TisN0M0, T1N0M0, or T2N0M0 squamous cell carcinoma of the glottic larynx diagnosed between 2004 and 2012 and undergoing definitive radiation therapy. Dose per fraction was calculated to define cohorts undergoing conventional fractionation (CFxn) and hypofractionation (HFxn). Logistic regression was performed to identify predictors of receiving HFxn, and Cox regression was used to determine predictors of death. One-to-one propensity score matching was then used to compare survival between fractionation schedules. The study included 10,539 patients, with 6576 undergoing CFxn and 3963 undergoing HFxn. Patients with T1 disease comprised a majority of each cohort. Use of HFxn increased significantly over the period studied (P<.001), but even in the final year, nearly one-half of patients continued to receive CFxn. Receipt of HFxn was also independently associated with higher income and facility types other than community cancer programs on logistic regression. On multivariate Cox regression, HFxn was associated with improved survival (hazard ratio [HR] for death, 0.90; 95% confidence interval [CI], 0.83-0.97; P=.008), a finding redemonstrated on univariate Cox regression among a well-matched cohort after propensity score matching (HR, 0.88; 95% CI, 0.80-0.96; P=.003). Subgroup Cox multivariate analysis demonstrated a significant survival advantage with HFxn among patients with T1 disease (HR, 0.90; 95% CI, 0.81-0.99; P=.042) but a nonsignificant benefit among those with Tis (HR, 0.86; 95% CI, 0.57-1.30; P=.472) or T2 (HR, 0.88; 95% CI, 0.76-1.02; P=.099) disease. Use of HFxn is increasing and is associated with improved survival over CFxn. Our findings support the broadened use of HFxn for patients with early-stage glottic cancer undergoing definitive radiation therapy.