[1] Univ Tokyo, Grad Sch Med, Dept Surg, Hepatobiliary Pancreat Surg Div, Tokyo, Japan
[2] Hokkaido Univ, Grad Sch Med, Dept Gastroenterol Surg 1, Sapporo, Japan
[3] Kyoto Univ, Grad Sch Med, Dept Surg, Kyoto, Japan
[4] Osaka Metropolitan Univ, Dept Hepatobiliary Pancreat Surg, Grad Sch Med, Osaka, Japan
[5] Fujita Hlth Univ, Dept Surg, Toyoake, Japan
[6] Tokyo Med & Dent Univ, Grad Sch Med, Dept Hepatobiliary & Pancreat Surg, Tokyo, Japan
[7] Japanese Red Cross Osaka Hosp, Dept Surg, Osaka, Japan
[8] Kumamoto Univ, Grad Sch Life Sci, Dept Gastroenterol Surg, Kumamoto, Japan
[9] Univ Tokyo, Sch Publ Hlth, Dept Biostat, Tokyo, Japan
[10] Yokohama City Univ, Dept Gastroenterol Surg, Yokohama, Japan
[11] Wakayama Med Univ, Dept Surg 2, Wakayama, Japan
[12] Tokyo Womens Med Univ, Inst Gastroenterol, Dept Surg, Tokyo, Japan
[13] Natl Ctr Global Hlth & Med, Dept Surg, Tokyo, Japan