Optimal Hospital Volume to Minimize Postoperative Mortality After Esophagectomy for Cancer in Low Population Density Countries: A Binational Study of Australia and New Zealand

BACKGROUND: A relationship between hospital volume and postoperative mortality following esophagectomy for cancer has been reported in Europe and USA, leading to centralization of surgery for esophageal cancer in some countries. It is unclear if this is replicated in countries with low population density such as Australia and New Zealand (ANZ). This study determined the relationship between hospital volume and mortality following esophagectomy in ANZ to define optimal hospital caseload. METHODS: As the standard of care following esophagectomy in ANZ is admission to an intensive care unit (ICU), the prospective ANZ Intensive Care Society Adult Patient Database was used to identify patients undergoing esophagectomy from 2005 to 2022. In-hospital mortality was first determined for hospitals with annual caseloads defined as high (18+), medium-high (12-17), medium-low (6-11), and low (1-5). To define optimal caseload, mortality was also analyzed against hospital volume using piecewise linear regression and nonlinear (restricted cubic spline) methods. RESULTS: Six thousand two hundred thirty-four patients underwent esophagectomy in 161 hospitals. Twenty-five percent of procedures were performed in low-volume hospitals (n = 1558) and 19.9% in high-volume hospitals (n = 1239). Overall, in-hospital mortality ranged from 0.73% in the highest volume hospitals to 5.71% in the lowest volume hospitals. High-volume hospitals also had a shorter length of stay in hospital (p < 0.001) and ICU (p < 0.001). The optimal annual hospital volume for the lowest mortality was identified as 21 cases per year. After adjusting for confounders in multivariable analysis, low-volume hospitals showed the highest risk of mortality with ORs of 3.98 (low), 3.39 (medium-low), and 3.32 (medium-high) versus high-volume (all p < 0.05). CONCLUSIONS: A positive volume-outcome relationship in ANZ was demonstrated for mortality following esophagectomy, with hospitals performing 21 or more surgeries per year delivering lowest mortality.