1. Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
2. Department of Hepato-Biliary-Pancreatic Medicine, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo 135-8550, Japan
3. Department of Gastroenterology, Graduate School of Medicine, Juntendo University, Tokyo 113-8431, Japan
4. Department of Surgery, Imusumiyoshi General Hospital, Saitama 354-0041, Japan
5. Department of Gastroenterology, National Hospital Organization, Kure Medical Center and Chugoku Cancer Center, Hiroshima 737-0023, Japan
6. Department of Gastroenterology, Japanese Red Cross Aichi Medical Center Nagoya Daini Hospital, Aichi 466-8650, Japan
7. Department of Surgery, Gastrointestinal Center, Yokohama Shin-Midori General Hospital, Kanagawa 226-0025, Japan
8. Department of Surgery, Kobe Tokushukai Hospital, Hyogo 655-0017, Japan
9. Department of Gastroenterology, Kameda Medical Center, Chiba 296-8602, Japan
10. Department of Gastroenterological Surgery, Hiroshima Prefectural Hospital, Hiroshima 734-8530, Japan
11. Department of Surgery, National Hospital Organization Sagamihara Hospital, Kanagawa 252-0392, Japan
12. Department of Gastroenterology, Sin-Kuki General Hospital, Saitama 346-8530, Japan
13. Department of Surgery, Toho University Ohashi Medical Center, Tokyo 153-8515, Japan