Esophagectomy performed at institutes certified by the Japan Esophageal Society provide long-term survival advantages to esophageal cancer patients: second report analyzing 4897 cases with propensity score matching

Background It will be important for the Japan Esophageal Society (JES) to show an evident advantage of its institution certification system. To achieve this essential task, we used nationally acquired big data to re-analyze 5-year survival information. Methods In 2008–2009, there were 4897 thoracic esophageal cancer patients who underwent esophagectomy and were registered in the National Database of Hospital-based Cancer Registries. We divided these patients into two groups, those who underwent surgery at an Authorized Institute for Board Certified Esophageal Surgeons (AIBCES) or a Non-AIBCES. We then compared the patient backgrounds and 5-year survival rates between these two groups, with and without propensity score matching. Results There were 3080 (63%) patients who underwent esophagectomy at an AIBCES and 1817 (37%) who underwent surgery at a Non-AIBCES. Comparison of the Kaplan–Meier survival curves using log-rank tests indicated a significant difference between the AIBCES and Non-AIBCES groups at all cStages (cStages I–IV). Multivariable Cox proportional hazard analysis stratified by clinical stage and adjuvant treatment revealed that AIBCES vs. Non-AIBCES is a significant independent factor (adjusted HR 0.78) for survival. After propensity score matching ensuring the backgrounds of the two groups being equivalent, there were significant differences in the 5-year survival rates for patients with cStages I–III disease between the AIBCES and Non-AIBCES groups. Conclusions There is a survival advantage to undergoing esophagectomy at an AIBCES. The institute certification system from the JES will contribute to the future establishment of a more appropriate surgery delivery system for thoracic esophageal cancer.