1. Department of Medical Oncology Kyorin University Faculty of Medicine Tokyo Japan
2. Second Department of Surgery Wakayama Medical University School of Medicine Wakayama Japan
3. Department of Gastroenterology Kanagawa Cancer Center Yokohama Japan
4. Department of Pancreatic Surgery Fudan University Shanghai Cancer Center Shanghai China
5. Division of Hepatobiliary and Pancreatic Surgery Cancer Institute Hospital, Japanese Foundation for Cancer Research Tokyo Japan
6. Department of Hepatobiliary and Pancreatic Surgery National Cancer Center Hospital East Kashiwa Japan
7. Department of Gastroenterological Surgery Osaka International Cancer Institute Osaka Japan
8. Division of Hepato‐Biliary‐Pancreatic Surgery Shizuoka Cancer Center Hospital Shizuoka Japan
9. Department of Hepato‐Biliary and Pancreatic Surgery Kanagawa Cancer Center Yokohama Japan
10. Department of Surgery Kindai University Faculty of Medicine Osakasayama Japan
11. Department of Gastroenterological Surgery Aichi Cancer Center Hospital Nagoya Japan
12. Department of Surgical Oncology Gifu University Graduate School of Medicine Gifu Japan
13. Department of Surgery Kansai Medical University Hirakata Japan
14. Department of General Surgery, Graduate School of Medicine Chiba University Chiba Japan
15. Department of Gastroenterological Surgery Nagoya University Graduate School of Medicine Nagoya Japan
16. Department of Hepatobiliary and Pancreatic Surgery National Cancer Center Hospital Tokyo Japan
17. Department of Biostatistics Yokohama City University School of Medicine Yokohama Japan