Trends and outcomes of proton radiation therapy use for non-small cell lung cancer

Purpose: To examine national care patterns in proton radiation therapy (PBT) use for non-small cell lung cancer (NSCLC) and the effect of facility type on survival. Patients and Methods: Using the National Cancer Database, we identified 506 patients with a diagnosis of NSCLC from 2004-2014 who underwent PBT. Patients were categorized as having received treatment at an academic/research facility (ARF) or a form of community cancer program (CCP). Descriptive analysis was performed, and overall survival was analyzed by Kaplan-Meier methods and Cox proportional hazard models. Results: Treatments at ARFs and CCPs were equally distributed with 253 patients at each facility type. A positive trend in PBT use over time was observed with 2.8% of cases being treated in 2008 compared to 21.5% in 2014 (P =.001). Definitive doses (≥60 Gy) were more commonly given at ARFs than CCPs (72% versus 45%, respectively; P , .001). Five-year overall survival was 31% at ARFs and 18% at CCPs (P ,<001). On multivariate analysis, outcomes were worse with treatments at CCPs (hazard ratio [HR] 1.61; 95% Confidence Interval, 1.14-2.27; P =.007). On subanalysis of nonsurgical patients treated with ≥60 Gy, facility type became insignificant and dose escalation was associated with improved outcomes (≥70 Gy HR 0.45; 95% CI, 0.25- 0.81; P =.008). Conclusion: Use of PBT for management of NSCLC is on the rise. Community cancer programs were associated with higher rates of nondefinitive PBT doses and correspondingly worse outcomes. Differences in survival by facility became insignificant when definitive doses were used, warranting further investigation of practice patterns in CCPs at a national level.