1. Department of Gastroenterological Surgery Graduate School of Medicine Yokohama City University Yokohama City Japan
2. Department of Surgery Nara Medical University Kashihara City Japan
3. Department of Hepatobiliary Pancreatic and Transplant Surgery Mie University Graduate School of Medicine Tsu City Japan
4. Department of Surgery Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital Bunkyo‐ku Japan
5. Department of Gastroenterological Surgery Ⅱ Faculty of Medicine Hokkaido University Sapporo City Japan
6. Department of Surgery Niigata Prefectural Central Hospital Joetsu City Japan
7. Department of Surgery Nagaoka Chuo General Hospital Nagaoka City Japan
8. Department of Surgery Hamamatsu University School of Medicine Hamamatsu City Japan
9. Department of Surgery Kansai Rosai Hospital Amagasaki City Japan
10. Department of Surgical Oncology Graduate School of Medicine Gifu University Gifu City Japan
11. Department of Surgery Shiga University of Medical Science Otsu City Japan
12. Department of Surgery Kimitsu Chuo Hospital Kisarazu City Japan
13. Department of Gastroenterological Surgery Akita University Graduate School of Medicine Akita City Japan
14. Department of Surgery Iwakuni Medical Center Iwakuni City Japan
15. Department of Surgery Bell Land General Hospital Sakai City Japan
16. Department of Surgery Okayama Saiseikai General Hospital Okayama City Japan
17. Department of Digestive Surgery, Breast and Thyroid Surgery Graduate School of Medical and Dental Sciences Kagoshima University Kagoshima City Japan
18. Department of Surgery Ibaraki Prefectural Central Hospital Kasama City Japan
19. Department of Gastroenterological Surgery Kumamoto University Kumamoto City Japan
20. Department of Surgery Japanese Red Cross Kumamoto Hospital Kumamoto City Japan
21. Department of Surgery Saitama Medical Center Jichi Medical University Sitama City Japan
22. 2nd Department of Surgery Wakayama Medical University Wakayama City, Wakayama Japan
23. Department of Surgery Institute of Gastroenterology Tokyo Women`s Medical University Tokyo Japan