1. Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine , Osaka , Japan
2. Japan Clinical Oncology Group Data Centre/Operations Office, National Cancer Centre Hospital , Tokyo , Japan
3. Department of Gastric Surgery, National Cancer Centre Hospital , Tokyo , Japan
4. Department of Gastrointestinal Surgery, Kanagawa Cancer Centre , Yokohama , Japan
5. Department of Surgery, Sakai City Medical Centre , Osaka , Japan
6. Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Science , Nagoya , Japan
7. Department of Surgery, Keiyukai Sapporo Hospital , Sapporo , Japan
8. Department of Surgery, Yamagata Prefectural Central Hospital , Yamagata , Japan
9. Department of Surgery, Tokyo Metropolitan Cancer and Infectious Diseases Centre Komagome Hospital , Tokyo , Japan
10. Department of Surgery, Toyama Prefectural Central Hospital , Toyama , Japan
11. Department of Surgery, National Hospital Organization Osaka National Hospital , Osaka , Japan
12. Department of Surgery, Yodogawa Christian Hospital , Osaka , Japan
13. Department of Gastric Surgery, Shizuoka Cancer Centre , Mishima , Japan