Department of Surgery, Division of Hepato-Biliary-Pancreatic Surgery, Kobe University Graduate School of Medicine, Hyogo, Japan. Department of Surgery, Kindai University Faculty of Medicine, Osaka, Japan. Department of Surgery, Seirei Mikatahara General Hospital, Shizuoka, Japan. Department of Surgery, Yodogawa Christian Hospital, Osaka, Japan. Department of Surgery, Saiseikai Suita Hospital, Osaka, Japan. Department of Surgery, Japan Red Cross Kobe Hospital, Hyogo, Japan. Department of Surgery, Kobe Rosai Hospital, Hyogo, Japan. Department of Gastroenterological Surgery, Kagawa University, Kagawa, Japan. Department of Surgery, Steel Memorial Hirohata Hospital, Hyogo, Japan. Department of Surgery, Hyogo Prefectural Kakogawa Medical Center, Hyogo, Japan. Clinical Translational Research Center of Kobe University Hospital, Hyogo, Japan. Department of Preventive Medicine and Epidemiology, National Cerebral and Cardiovascular Center, Osaka, Japan.