1. Department of Gastroenterological Surgery Graduate School of Medicine Osaka University Suita Japan
2. Division of Hepatobiliary‐Pancreatic Surgery Cancer Institute Hospital Tokyo Japan
3. Department of Gastrointestinal and Pediatric Surgery Tokyo Medical University Tokyo Japan
4. Department of Hepatobiliary and Pancreatic Oncology National Cancer Center Hospital Tokyo Japan
5. Department of Gastroenterological Surgery Nagoya University Graduate School of Medicine Nagoya Japan
6. Department of Surgery Tohoku University Graduate School of Medicine Sendai Japan
7. Department of Surgery Kansai Medical University Hirakata Japan
8. Department of Gastroenterological Surgery Aichi Cancer Center Hospital Nagoya Japan
9. Center for Gastroenterology Teine‐keijinkai Hospital Sapporo Japan
10. Department of Surgery Institute of Gastroenterology Tokyo Women's Medical University Tokyo Japan
11. Department of Surgery Kurashiki Central Hospital Kurashiki Japan
12. Department of Biomedical Statistics Graduate School of Medicine Osaka University Suita Japan
13. Department of Surgery and Science Faculty of Medicine, Academic Assembly University of Toyama Toyama Japan
14. Department of Gastroenterology and Hepatology Fujita Health University Toyoake Japan
15. Igarashi Medical Clinic Shimonoseki Japan
16. Second Department of Internal Medicine Wakayama Medical University School of Medicine Wakayama Japan
17. Department of Surgery National Hospital Organization Nagasaki Medical Center Ohmura Japan
18. Division of Gastroenterology Tohoku University Graduate School of Medicine Sendai Japan
19. Department of Surgery Shiga University of Medical Science Otsu Japan
20. Department of Gastroenterology IMS Sapporo Digestive Disease Center General Hospital Sapporo Japan
21. Department of General Medicine Sapporo Medical University Sapporo Japan
22. Second Department of Surgery Wakayama Medical University Wakayama Japan
23. Division of Surgical Oncology University of Colorado Anschutz Medical Campus Aurora Colorado USA
24. Department of Surgery Kindai University Faculty of Medicine Osaka Japan