1. Second Department of Surgery Wakayama Medical University Wakayama Japan
2. Department of Hepato‐Biliary‐Pancreatic Surgery Osaka Metropolitan University Graduate School of Medicine Osaka Japan
3. Department of Gastroenterological Surgery, Graduate School of Medical Sciences Kumamoto University Kumamoto Japan
4. Department of Surgery and Science, Faculty of Medicine, Academic Assembly University of Toyama Toyama Japan
5. Department of Surgery Kindai University Faculty of Medicine Osaka‐Sayama Japan
6. Department of Surgery Kansai Medical University Hirakata Japan
7. Department of Surgical Oncology Gifu University Graduate School of Medicine Gifu Japan
8. Department of Gastroenterological Surgery Nagoya University Graduate School of Medicine Nagoya Japan
9. Department of Surgery Nara Medical University Kashihara Japan
10. Division of Hepato‐Biliary‐Pancreatic Surgery, Department of Gastroenterological Surgery Hyogo Medical University Nishinomiya Japan
11. Department of Gastroenterological Surgery, Graduate School of Medicine Osaka University Suita Japan
12. Department of General and Gastroenterological Surgery Osaka Medical and Pharmaceutical University Takatsuki Japan
13. Department of Surgery Shiga University of Medical Science Ōtsu Japan
14. Division of Hepato‐Biliary‐Pancreatic Surgery and Transplantation, Department of Surgery, Graduate School of Medicine Kyoto University Kyoto Japan
15. Division of Digestive Surgery, Department of Surgery Kyoto Prefectural University of Medicine Kyoto Japan
16. Clinical Study Support Center Wakayama Medical University Wakayama Japan
17. Department of Cancer Immunology Wakayama Medical University Wakayama Japan