1. Department of Gastroenterological Surgery, Cancer Institute Ariake Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan
2. Department of Frontier Surgery, Chiba University Graduate School of Medicine, Chiba, Japan
3. Department of Gastroenterological Surgery, Ishikawa Prefectural Central Hospital, Kanazawa, Japan
4. Department of Surgery, Tonan Hospital, Sapporo, Japan
5. Department of Surgery, Kyorin University School of Medicine, Tokyo, Japan
6. Center for Cancer Control and Statistics, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan
7. Department of Surgery, Toho University Ohashi Medical Center, Tokyo, Japan
8. Department of Gastroenterological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.