1. Department of Surgery; Teikyo University School of Medicine; Tokyo Japan
2. Department of Surgery; Institute of Gastroenterology; Tokyo Women's Medical University Hospital; Tokyo Japan
3. Department of Surgery; Okayama Saiseikai General Hospital; Okayama Japan
4. Department of Gastroenterological Surgery; Yokohama City University Graduate School of Medicine; Yokohama Japan
5. Department of Hepatobiliary-Pancreatic Surgery; National Hospital Organization; Osaka National Hospital; Osaka Japan
6. Department of Hepatobiliary-Pancreatic Surgery; National Cancer Center Hospital East; Tokyo Japan
7. Department of General Surgery; Graduate School of Medicine; Chiba University; Chiba Japan
8. Division of Digestive and General Surgery; Niigata University Graduate School of Medical and Dental Sciences; Niigata Japan
9. Division of Surgical Oncology; Department of Surgery; Nagoya University Graduate School of Medicine; Nagoya Japan
10. Second Department of Surgery; Dokkyo Medical University; Mibu Japan
11. Department of Surgery; Tohoku University Graduate School of Medicine; Sendai Japan
12. Department of Surgery; Jichi Medical University; Shimotsuke Japan
13. Department of Surgery; National Defense Medical College; Tokorozawa Japan
14. Second Department of Surgery; Wakayama Medical University; Wakayama Japan