1. Department of Surgery, Graduate School of Medicine, Kyoto University , Kyoto
2. Division of Esophageal Surgery, Shizuoka Cancer Center , Shizuoka
3. JCOG Data Center/Operations Office, National Cancer Center Hospital , Tokyo
4. Department of Gastroenterological Surgery, Tokai University School of Medicine , Isehara
5. Department of Surgery, Hamamatsu University School of Medicine , Hamamatsu
6. Department of Surgery, Tohoku University Graduate School of Medicine , Sendai
7. Department of Esophageal and Gastroenterological Surgery, Juntendo University Graduate School of Medicine , Tokyo
8. Department of Gastroenterological Surgery, Okayama University Graduate School of Medicine , Okayama
9. Gastrointestinal Medical Oncology Division, National Cancer Center Hospital , Tokyo
10. Department of Surgery, Keio University School of Medicine , Tokyo , Japan