1. Department of Surgery, Asan Medical Center University of Ulsan College of Medicine Seoul South Korea
2. Department of Surgery Kansai Medical University Hirakata Japan
3. Department of Surgery, Samsung Medical Center Sungkyunkwan University School of Medicine Seoul South Korea
4. Department of Surgery, Severance Hospital Yonsei University College of Medicine Seoul South Korea
5. Department of Gastroenterological Surgery Hiroshima University Hospital Hiroshima Japan
6. Department of surgery Iizuka Hospital Iizuka Japan
7. Department of Surgery Hwasun Chonnam National University Hospital and Medical School Gwangju South Korea
8. Second Department of Surgery Dokkyo Medical University Tochigi Japan
9. Department of Surgery Japanese Red Cross Osaka Hospital Osaka Japan
10. Department of Surgery Kansai Rosai Hospital Amagasaki Japan
11. Department of Surgery Yeungnam University Medical Center Daegu South Korea
12. Department of Gastroenterological Surgery Hyogo College of Medicine Nishinomiya Japan
13. Department of Gastroenterological, Breast and Endocrine Surgery Yamaguchi University Graduate School of Medicine Ube Japan
14. Department of Surgery Pusan National University Hospital Kumjeong‐ku South Korea
15. Department of Surgery Shinshu University School of Medicine Matsumoto Japan
16. Institute of Gastroenterology Tokyo Women's Medical University Tokyo Japan
17. Department of Surgery Kyung Hee University Medical Center Seoul South Korea
18. Department of Surgery Inje University Busan Paik Hospital Busan South Korea
19. Department of Surgery Jeonbuk National University Hospital Jeonju South Korea
20. Department of Surgery Ajou University School of Medicine Suwon South Korea
21. Department of Clinical Epidemiology and Biostatistics, Asan Medical Center University of Ulsan College of Medicine Seoul South Korea
22. Center for Liver and Pancreatobiliary Cancer National Cancer Center Goyang South Korea
23. Department of Surgery Seoul National University College of Medicine Seoul South Korea
24. Second Department of Surgery Wakayama Medical University Wakayama Japan
25. Department of Surgery and Oncology, Graduate School of Medical Sciences Kyushu University Fukuoka Japan
26. Department of Surgery Utsunomiya Memorial Hospital Tochigi Japan
27. Gastroenterological Surgery Yokohama City University Graduate School of Medicine Kanagawa Japan