Closing the gap: Contribution of surgical best practices to outcome differences between high- and low-volume centers for lung cancer resection

Background: Clinical outcomes for resected early-stage non-small cell lung cancer (NSCLC) are superior at high-volume facilities, but reasons for these differences remain unclear. Understanding these differences and optimizing outcomes across institutions are critical to the management of the increasing incidence of these cases. We evaluated the extent to which surgical best practices account for resected early-stage NSCLC outcome differences between facilities according to case volume. Methods: We performed a retrospective cohort study for clinical stage 1 or 2 NSCLC undergoing surgical resection from 2004 to 2013 using the National Cancer Database (NCDB). Surgical best practices (negative surgical margins, lobar or greater resection, lymph node (LN) dissection, and examination of > 10 LNs) were compared between the highest and lowest quartile volumes. Results: A total of 150,179 patients were included in the cohort (89% white, 53% female, median age 68 years). In a multivariate model, superior overall survival (OS) was observed at highest volume centers compared to lowest volume centers (hazard ratio (HR) = 0.89; 95% CI, 0.82-0.96; P =.002). After matching for surgical best practices, there was no significant OS difference (HR = 0.95; 95% CI, 0.87-1.05; P =.32). Propensity score-adjusted HR estimates indicated that surgical best practices accounted for 54% of the numerical OS difference between low-volume and high-volume centers. Each surgical best practice was independently associated with improved OS (all P ≤.001). Conclusion: Quantifiable and potentially modifiable surgical best practices largely account for resected early-stage NSCLC outcome differences observed between low- and high-volume centers. Adherence to these guidelines may reduce and potentially eliminate these differences.