1. Department of Surgery, Ichinomiya Municipal Hospital, Ichinomiya, Japan.
2. Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, Nagoya, Japan.
3. Department of Gastroenterological Surgery, Aichi Cancer Center, Nagoya, Japan.
4. Department of Surgery, Komaki Municipal Hospital, Komaki, Japan.
5. Department of Surgery, Yokkaichi Municipal Hospital, Yokkaichi, Japan.
6. Department of Surgery, Konan Kosei Hospital, Konan, Japan.
7. Department of Surgery, Gifu Prefectural Tajimi Hospital, Tajimi, Japan.
8. Department of Surgery, Okazaki City Hospital, Okazaki, Japan.
9. Department of Surgery, Tosei General Hospital, Seto, Japan.
10. Biostatistics Center, Graduate School of Medicine, Kurume University, Kurume, Japan.