1. Department of Gastroenterological Surgery, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo, Japan
2. Department of Gastrointestinal Surgery, Kanagawa Cancer Centre, Yokohama, Japan
3. Department of Biostatistics and Epidemiology, Yokohama City University Medical Centre, Yokohama, Japan
4. Department of Gastroenterological Surgery, Aichi Cancer Centre, Nagoya, Japan
5. Department of Surgery, Osaka General Medical Centre, Osaka, Japan
6. Division of Gastroenterological Surgery, Chiba Cancer Centre, Chiba, Japan
7. Division of Gastroenterological Surgery, Saitama Cancer Centre, Saitama, Japan
8. Department of Surgery, Osaka Medical Centre, Osaka, Japan
9. Department of Surgery, Hyogo College of Medicine, Nishinomiya, Japan