Relationship Between Hospital Volume and Outcomes of Minimally Invasive Esophagectomy for Esophageal Cancer: Analysis of the National Clinical Database in Japan

Aim While esophagectomy is a high‐difficulty procedure, minimally invasive esophagectomy (MIE) requires even more advanced surgical skills, necessitating analysis of factors affecting surgical outcomes. This study examined the relationship between the postoperative mortality and complication rates of MIE and the annual hospital volume of esophagectomy to identify a threshold volume serving as a safety benchmark. Methods We analyzed data from 22 712 patients registered in the National Clinical Database who underwent esophagectomy (MIE or open esophagectomy [OE]) at 1 037 hospitals in Japan between January 1, 2012, and December 31, 2015. Hospitals were stratified into five categories according to average annual volume of esophagectomies (MIE and OE). The primary outcome was operative mortality, and the secondary outcome was the incidence of postoperative complications. Results The 22 712 cases consisted of 9 739 cases (42.9%) of MIE and 12 973 cases (57.1%) of OE. Regarding MIE outcomes, the overall crude perioperative mortality and perioperative complication rates were 2.1% and 40.9%, respectively. Multivariable analysis performed using very‐high‐volume hospitals as reference revealed an odds ratio for mortality in very‐low‐volume hospitals of 2.70 ( p < 0.0001). Conclusion The postoperative mortality rate in patients undergoing MIE was relatively low in hospitals with a higher annual average volume of esophagectomy cases. Mortality was significantly higher in hospitals performing five or fewer esophagectomies annually. However, residual confounding due to differences in baseline patient characteristics cannot be excluded, although key clinical factors were adjusted for. Therefore, careful attention must be paid to the surgical and perioperative management techniques when performing MIE, particularly in very‐low‐volume hospitals.