1. Department of Hepato‐Biliary‐Pancreatic and Gastrointestinal Surgery, School of Medicine International University of Health and Welfare Chiba Japan
2. Department of Gastroenterological Surgery Osaka International Cancer Institute Osaka Japan
3. Department of Surgery Keio University School of Medicine Tokyo Japan
4. Department of Surgery, Kansai Rosai Hospital Japan Organization of Occupational Health and Safety Osaka Japan
5. Department of Surgery Nagasaki University Graduate School of Biomedical Sciences Nagasaki Japan
6. Department of Surgery Eiju General Hospital Tokyo Japan
7. Department of Surgery Tokyo Women's Medical University Tokyo Japan
8. Department of Surgery Shizuoka City Shizuoka Hospital Shizuoka Japan
9. Department of Surgery Kurashiki Central Hospital Kurashiki Japan
10. Department of Hepatobiliary and Pancreatic Surgery National Cancer Center Hospital Tokyo Japan
11. Department of Gastroenterological Surgery Ehime Prefectural Central Hospital Matsuyama Japan
12. Department of Surgery Tamakyuryu Hospital Tokyo Japan
13. Department of Surgery Hamamatsu‐Minami Hospital Shizuoka Japan
14. Department of Gastroenterological, Breast and Endocrine Surgery Yamaguchi University Graduate School of Medicine Yamaguchi Japan