1. Department of Surgery Kochi Medical School Nankoku Japan
2. Department of Healthcare Quality Assessment Graduate School of Medicine The University of Tokyo Bunkyo‐ku Japan
3. Project Management Subcommittee The Japanese Society of Gastroenterological Surgery Tokyo Japan
4. Database Committee The Japanese Society of Gastroenterological Surgery Tokyo Japan
5. Department of Surgical Oncology Graduate School of Medicine Gifu University Gifu Japan
6. Department of Gastrointestinal Surgery Graduate School of Medicine The University of Tokyo Bunkyo‐ku Japan
7. Second Department of Surgery School of Medicine Wakayama Medical University Wakayama Japan
8. Department of Surgery Institute of Gastroenterology Tokyo Women's Medical University Shinjuku‐ku Japan
9. The Japanese Society of Gastroenterological Surgery Tokyo Japan