1. Nagoya University, Nagoya, Japan;
2. Department of Surgical Oncology, Gifu University Graduate School of Medicine, Gifu, Japan;
3. Department of Digestive Surgery, Nihon University Itabashi Hospital, Tokyo, Japan;
4. Division of Medical Oncology, Showa University Fujigaoka Hospital, Yokohama, Japan;
5. Division of Gastrointestinal Surgery, Department of Surgery, Kobe University Graduate School of Medicine, Kobe, Japan;
6. Japanese Foundation for Cancer Research Cancer Institute Hospital, Tokyo, Japan;
7. Department of Surgery, Gifu Prefectural General Medical Center, Gifu, Japan;
8. Division of Gastroenterological Surgery, Yokohama Municipal Citizen's Hospital, Yokohama, Japan;
9. Hakodate Goryoukaku Hospital, Hakodate, Japan;
10. Department of Surgery, Konan Kosei Hospital, Konan, Japan;
11. Toyama Prefectural Central Hospital, Toyama, Japan;
12. Department of Surgery, Tokushima Red Cross Hospital, Komatsushima, Japan;
13. Department of Surgery, Yamagata Prefectural Central Hospital, Yamagata, Japan;
14. Department of Gastrointestinal Surgery, Aichi Cancer Center Aichi Hospital, Okazaki, Japan;
15. Kanagawa Cancer Center, Kanagawa, Japan;
16. Department of Surgery, Yao Municipal Hospital, Yao, Japan;
17. Department of Surgery, Gifu Municipal Hospital, Gifu, Japan;
18. Aichi Cancer Center Hospital, Aichi, Japan;
19. Department of Clinical Medicine (Biostatistics), School of Pharmacy, Kitasato University, Tokyo, Japan;
20. Department of Digestive Surgery, Nihon University School of Medicine, Tokyo, Japan;