Background: The relationship between provider experience and clinical outcomes is poorly defined in radiation oncology. This study examined the impact of facility case volume on overall survival in patients with stage III non-small cell lung cancer (NSCLC) treated with definitive concurrent chemoradiation therapy (CCRT).
Methods: Using the National Cancer Data Base, we identified clinical stage III NSCLC patients diagnosed in 2004 to 2006 who were treated with definitive CCRT to 59.4-74.0 Gy. High-volume facilities (HVF) were defined as those in the ninetieth percentile of annual CCRT volume (≥12 cases/year). Independent predictors of receiving CCRT at HVF were identified using multivariable logistic regression. Overall survival based on receiving CCRT at HVF was assessed using Kaplan-Meier analysis, Cox proportional hazards regression, and propensity score matching.
Results: Among 10,072 included patients, 1207 (12.0%) were treated at HVF. Patients in HVF were more likely to have a higher Charlson-Deyo comorbidity score, more advanced nodal stage, higher doses, and 3D-conformal or intensity-modulated radiotherapy. When controlling for demographic and clinical covariates including academic affiliation, treatment at HVF was independently associated with a significantly decreased risk of death (hazards ratio = 0.93; 95% confidence interval: 0.87-0.99; p = 0.03). Propensity score matching showed that these findings were robust (hazards ratio = 0.91; 95% confidence interval: 0.84-0.99; p = 0.04).
Conclusions: Our findings suggest that treatment at HVF is associated with improved overall survival among stage III NSCLC patients receiving definitive CCRT, independent of academic affiliation. Further research is needed to determine whether or not efforts supporting centralization of radiotherapy at HVF will improve population-based survival, toxicities, and costs.