1. Department of Gastroenterology, Japan Labour Health and Welfare Organization, Yokohama Rosai Hospital, Yokohama, Japan
2. Department of Surgery, Tokyo Metropolitan Cancer and Infectious Disease Center, Komagome Hospital, Tokyo, Japan
3. Department of Gastrointestinal Surgery, Kanagawa Cancer Center, Yokohama, Japan
4. Department of Gastroenterological Surgery, Shizuoka General Hospital, Shizuoka, Japan
5. Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan
6. Department of Surgery, Tokai University, Isehara, Japan
7. Department of Surgery, Hitachi General Hospital, Hitachi, Japan
8. Department of Gastroenterology and Hepatology, International University of Health and Welfare, Mita Hospital, Tokyo, Japan
9. Department of Digestive and Transplantation Surgery, Tokyo Medical University Hachioji Medical Center, Tokyo, Japan
10. Second Department of Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan