[1] Yokohama City Univ, Grad Sch Med, Dept Surg Gastroenterol, Yokohama, Kanagawa 2360004, Japan
[2] Yokohama City Univ, Grad Sch Med, Dept Biostat & Epidemiol, Yokohama, Kanagawa 2360004, Japan
[3] Yokohama City Univ, Dept Surg, Gastroenterol Ctr, Yokohama, Kanagawa 2360004, Japan
[4] Kanto Med Ctr NTT EC, Dept Surg, Tokyo, Japan
[5] Yokohama City Univ, Dept Surg, Yokohama, Kanagawa 2360004, Japan
[6] Yokosuka Kyosai Hosp, Dept Surg, Yokosuka, Kanagawa, Japan
[7] Fujisawa City Hosp, Dept Surg, Fujisawa, Kanagawa, Japan
[8] Yokohama Med Ctr, Natl Hosp Org, Dept Surg, Yokohama, Kanagawa, Japan
[9] Yokohama City Minato Red Cross Hosp, Dept Surg, Yokohama, Kanagawa, Japan
[10] Ito Municipal Hosp, Dept Surg, Ito, Japan
[11] Yokohama Ekisaikai Hosp, Dept Surg, Yokohama, Kanagawa, Japan