1. Division of Gastrointestinal Medical Oncology, National Cancer Center Hospital , Tokyo, Japan
2. Health Science Research & Development Center , Tokyo Medical and Dental University, Tokyo, Japan
3. Japan Clinical Oncology Group Data Center /Operations Office, National Cancer Center Hospital , Tokyo, Japan
4. Department of Medical Oncology, Kyorin University Faculty of Medicine , Tokyo, Japan
5. Department of Gastroenterological Surgery, Gunma Prefectural Cancer Center , Gunma, Japan
6. Department of Gastroenterological Oncology, Saitama Medical University International Medical Center , Saitama, Japan
7. Department of Gastroenterology, University of Tsukuba Hospital , Tsukuba, Japan
8. Department of Clinical Oncology, Aichi Cancer Center Hospital , Aichi, Japan
9. Department of Gastroenterology, Saitama Cancer Center , Saitama, Japan
10. Department of Surgery, National Defense Medical College , Saitama, Japan
11. Division of Clinical Oncology, Hiroshima Prefectural Hospital , Hiroshima, Japan
12. Department of Medical Oncology, Osaka International Cancer Institute , Osaka, Japan
13. Department of Gastroenterology, Kanagawa Cancer Center , Yokohama, Japan
14. Department of Surgery, Fujita Health University School of Medicine , Toyoake, Japan
15. Department of Pathology , Saitama Medical Center, , Saitama, Japan
16. Saitama Medical University , Saitama Medical Center, , Saitama, Japan
17. Cancer Chemotherapy Center, Osaka Medical and Pharmaceutical University , Osaka, Japan
18. Department of Surgery, Niigata Cancer Center Hospital , Niigata, Japan
19. Department of Gastroenterological Surgery, Nippon Medical School , Tokyo, Japan
20. Department of Gastroenterology, Hyogo Cancer Center , Akashi, Hyogo, Japan
21. Department of Medical Oncology, Ishikawa Prefectural Central Hospital , Ishikawa, Japan
22. Department of Medical Oncology, Nagaoka Chuo General Hospital , Niigata, Japan
23. Division of Gastroenterology and Hepatology , Department of Internal Medicine, , Tokyo, Japan
24. The Jikei University School of Medicine , Department of Internal Medicine, , Tokyo, Japan
25. Department of Colorectal Surgery, National Cancer Center Hospital , Tokyo, Japan