1. Department of Hepatobiliary and Pancreatic Surgery Tokyo Medical and Dental University Tokyo Japan
2. Department of Gastroenterological Surgery Toranomon Hospital Tokyo Japan
3. Department of Surgery Nagasaki University Graduate School of Biomedical Sciences Nagasaki Japan
4. Department of Gastroenterological Surgery Yokohama City University Kanagawa Japan
5. Department of Hepato‐Biliary‐Pancreatic Surgery Osaka Metroplitan University Graduate School of Medicine Osaka Japan
6. Department of Gastroenterological Surgery I Hokkaido University Graduate School of Medicine Hokkaido Japan
7. Department of Gastroenterological, Breast and Endocrine Surgery Yamaguchi University Graduate School of Medicine Yamaguchi Japan
8. Department of Surgery and Oncology, Graduate School of Medical Sciences Kyushu University Fukuoka Japan
9. Hepato‐Biliary‐Pancreatic Surgery Division, Graduate School of Medicine The University of Tokyo Tokyo Japan
10. Department of Surgery, Graduate School of Medicine Kyoto University Kyoto Japan
11. Department of Surgery and Science, Graduate School of Medical Sciences Kyushu University Fukuoka Japan
12. Department of Surgery, Hepato‐Biliary Pancreatic Surgery Division National Center for Global Health and Medicine Tokyo Japan