1. Japan Clinical Oncology Group Data Center/Operations Office, National Cancer Center Hospital , Tokyo , Japan
2. Department of Surgery, Toyonaka Municipal Hospital , Osaka , Japan
3. Department of Gastroenterology, Chiba Cancer Center , Chiba , Japan
4. Department of Surgery, Hamamatsu University School of Medicine , Shizuoka , Japan
5. Division of Gastrointestinal Oncology, Shizuoka Cancer Center , Shizuoka , Japan
6. Department of Gastroenterological Surgery, Osaka University , Osaka , Japan
7. Department of Head and Neck , Esophageal Medical Oncology, , Tokyo , Japan
8. National Cancer Center Hospital , Esophageal Medical Oncology, , Tokyo , Japan
9. Department of Surgery, Keio University School of Medicine , Tokyo , Japan
10. Department of Oncology and General Medicine , Institute of Medical Science, , Tokyo , Japan
11. University of Tokyo , Institute of Medical Science, , Tokyo , Japan
12. Gastrointestinal Medical Oncology Division, National Cancer Center Hospital , Tokyo , Japan
13. Division of Gastric Surgery, Shizuoka Cancer Center , Nagaizumi , Japan