1. Gastroenterological and Pediatric Surgery Oita University of Faculty of Medicine Yufu Japan
2. Japan Clinical Oncology Group Data Center/Operations Office National Cancer Center Hospital Tokyo Japan
3. Department of Colorectal Surgery National Cancer Center Tokyo Japan
4. Department of Surgery Osaka International Cancer Institute Osaka Japan
5. Department of Colorectal Surgery National Cancer Center Hospital East Kashiwa Japan
6. Department of Gastrointestinal Surgery Tokyo Medical and Dental University Tokyo Japan
7. Department of Colorectal Surgery Toho University Tokyo Japan
8. Department of Surgery Kyorin University Tokyo Japan
9. Department of Surgery Fujita Health University Aichi Japan
10. Department of Gastroenterological Surgery Saitama Medical University International Medical Center Saitama Japan
11. Department of Surgery Kitasato University School of Medicine Sagamihara Japan
12. Department of Surgery Tokyo Medical and Dental University Tokyo Japan