Abstract
PURPOSE: The optimal delivery schedule for stereotactic body radiation therapy (SBRT) in treating stage I non-small cell lung cancer (NSCLC) is unknown. This study used the National Cancer Database to examine daily versus every other day (QOD) SBRT scheduling, including trends over time and association with survival. METHODS AND MATERIALS: The National Cancer Database was used to retrospectively identify patients with stage I NSCLC treated with 3-, 4-, or 5-fraction of SBRT between 2004 and 2016. Survival analysis was performed using the Kaplan-Meier method and Cox regression modeling. RESULTS: Of 15,269 patients, 3927 (25.7%) received SBRT daily, and 11,342 (74.3%) received treatment QOD. The use of QOD treatment increased from 63.2% in 2007 to 78.3% in 2016, and 5-fraction SBRT increased from 3.7% in 2004 to 51.4% in 2016 (both P < .0001). QOD 5-fraction became the most prevalent scheduling from 2012 to 2016 (28.5% in 2012 to 41.6% in 2016). Factors significantly associated with daily SBRT scheduling included number of fractions, race, lower income, lower comorbidities, and treatment at academic/research programs (all P ≤ .01).Median survival for daily SBRT was 37.9 months versus 38.4 months for QOD (P = .4). On multivariable analysis, no difference was found in overall survival between daily versus QOD scheduling (adjusted hazard ratio [aHR], 0.99; 95% confidence interval [CI], 0.94-1.04; P = .55). Five-fraction SBRT was associated with worse survival versus 3 fractions (aHR, 1.09; 95% CI, 1.03-1.15; P = .002). With 3-fraction SBRT, QOD treatment was associated with improved survival versus daily treatment (aHR, 0.91; 95% CI, 0.84-0.98; P = .02). With 5-fraction SBRT, QOD treatment was associated with worse survival versus daily treatment (aHR, 1.11; 95% CI, 1.02-1.22; P = .02). CONCLUSIONS: QOD SBRT schedules were more frequently used to treat stage I NSCLC than daily regimens by a factor of 3:1, and QOD 5-fraction SBRT became the most common dose schedule after 2012. Three-fraction QOD SBRT was associated with improved survival versus daily, whereas 5-fraction QOD SBRT was associated with worse survival versus daily.