Effect of hospital and surgeon volume on postoperative outcomes after distal gastrectomy for gastric cancer based on data from 145,523 Japanese patients collected from a nationwide web-based data entry system

BackgroundDespite interest in surgeon and hospital volume effects on distal gastrectomy, clinical significance has not been confirmed in a large-scale population. We studied to clarify the effects of surgeon and hospital volume on postoperative mortality after distal gastrectomy for gastric cancer among Japanese patients in a nationwide web-based data entry system.MethodsWe extracted data on distal gastrectomy for gastric cancer from the National Clinical Database between 2011 and 2015. The primary outcome was operative mortality. Hospital volume was divided into 3 tertiles: low (1-22 cases per year), medium (23-51) and high (52-404). Surgeon volume was divided into the 5 groups: 0-3, 4-10, 11-20, 21-50, 51+cases per year. We calculated the 95% confidence interval (CI) for the mortality rate based on odds ratios (ORs) estimated from a hierarchical logistic regression model.ResultsWe analyzed 145,523 patients at 2182 institutions. Operative mortality was 1.9% in low-, 1.0% in medium- and 0.5% in high-volume hospitals. The operative mortality rate decreased definitively with surgeon volume, 1.6% in the 0-3 group and 0.3% in the 51+group. After risk adjustment for surgeon and hospital volume and patient characteristics, hospital volume was significantly associated with operative morality (medium: OR 0.64, 95% CI 0.56-0.73, P<0.001; high: OR 0.42, 95% CI 0.35-0.51, P<0.001).ConclusionsWe demonstrate that hospital volume can have a crucial impact on postoperative mortality after distal gastrectomy compared with surgeon volume in a nationwide population study. These findings suggest that centralization may improve outcomes after distal gastrectomy.