Redefining High-Volume Gastric Cancer Centers: The Impact of Operative Volume on Surgical Outcomes.

BACKGROUND: Performance of technically complex surgery at high-volume (HV) centers is associated with improved outcomes. OBJECTIVE: The aim of this study was to assess whether hospital gastrectomy volume is associated with surgical outcomes, and what threshold of case volume meaningfully impacts surgical outcomes. METHODS: We conducted a retrospective review of adult NCDB patients with gastric adenocarcinoma undergoing gastrectomy between 2004 and 2015. A multivariable Cox proportional hazards model with restricted cubic splines was used to examine the association of annual hospital gastrectomy volume and overall survival. Bootstrap simulation was used to estimate the cut-point corresponding to maximum change in log hazard ratio. Hospitals were divided into HV (≥ 17 cases/year) and low-volume (LV; < 17 cases/year) groups. We examined the relationship between volume groups and adequate nodal examination, R0 resection, unplanned readmission, and 30- and 90-day mortality. RESULTS: Our cohort consisted of 29,559 patients (7.8% treated at an HV center). Treatment at an HV center was associated with an increased likelihood of adequate nodal examination [odds ratio (OR) 2.12, 95% confidence interval (CI) 1.94-2.32] and R0 resection among patients with cardia tumors (OR 1.42, 95% CI 1.07-1.88). Patients treated at HV centers had decreased 30- and 90-day postoperative mortality, which was more pronounced in those undergoing total gastrectomy. CONCLUSIONS: Treatment at an HV gastrectomy center is associated with improved surgical outcomes. Our study identified 17 cases/year as a clinically meaningful distinction between HV and LV centers. This definition of an HV center should be considered when evaluating regionalization of gastric cancer care to improve patient outcomes.