1. Japan Clinical Oncology Group Data Center/Operations Office National Cancer Center Hospital Tokyo Japan
2. Department of Gastroenterological and Pediatric Surgery Oita University Faculty of Medicine Oita Japan
3. Department of Surgery Kitasato University Kitasato Institute Hospital Tokyo Japan
4. Department of Gastroenterological Surgery Tokai University School of Medicine Kanagawa Japan
5. Department of Colorectal Surgery National Cancer Center Hospital East Chiba Japan
6. Department of Gastrointestinal Surgery Tokyo Medical and Dental University Tokyo Japan
7. Department of Surgery Hiroshima City Hiroshima Citizens Hospital Hiroshima Japan
8. Department of Surgery Surgical Oncology and Science Sapporo Medical University Hokkaido Japan
9. General and Gastroenterological Surgery Osaka Medical College Osaka Japan
10. Department of Colorectal Surgery National Cancer Center Hospital Tokyo Japan
11. Oita University Oita Japan