1. Hepato-Biliary-Pancreatic Surgery Division, Department of Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
2. Department of Gastroenterological Surgery I, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
3. Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
4. Department of Hepato-Biliary-Pancreatic Surgery, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
5. Department of Surgery, Fujita Health University, Toyoake, Japan
6. Department of Hepatobiliary and Pancreatic Surgery, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
7. Department of Surgery, Japanese Red Cross Osaka Hospital, Osaka, Japan
8. Department of Gastroenterological Surgery, Graduate School of Life Sciences, Kumamoto University, Kumamoto, Japan
9. Department of Biostatistics, School of Public Health, The University of Tokyo, Tokyo, Japan
10. Department of Gastroenterological Surgery, Yokohama City University, Yokohama, Japan
11. Second Department of Surgery, Wakayama Medical University, Wakayama, Japan
12. Department of Surgery, Institute of Gastroenterology, Tokyo Women’s Medical University, Tokyo, Japan
13. Department of Surgery, National Center for Global Health and Medicine, Tokyo, Japan