[1] Hiroshima Univ Hosp, Dept Surg, Hiroshima, Japan
[2] Tokai Univ, Dept Surg, Isehara, Kanagawa, Japan
[3] Juntendo Univ, Fac Med, Dept Coloproctol Surg, Tokyo, Japan
[4] Sendai City Med Ctr, Dept Surg, Sendai, Miyagi, Japan
[5] Gifu Univ Hosp, Dept Gastrointestinal Surg, Gifu, Japan
[6] Yamagata Prefectural Cent Hosp, Dept Surg, Yamagata, Japan
[7] Nagoya Med Ctr, Dept Surg, Nagoya, Aichi, Japan
[8] Kurume Univ Hosp, Dept Canc Ctr, Kurume, Fukuoka, Japan
[9] Kumamoto Univ, Grad Sch Med Sci, Dept Gastroenterol Surg, Kumamoto, Japan
[10] Tokyo Womens Med Univ Hosp, Inst Gastroenterol, Dept Surg, Tokyo, Japan
[11] Hyogo Med Univ Hosp, Dept Gastroenterol Surg, Nishinomiya, Hyogo, Japan
[12] Kansai Med Univ Hosp, Div Gastrointestinal Surg, Hirakata, Osaka, Japan
[13] Yoichi Hosp, Dept Internal Med, Yoichi, Hokkaido, Japan
[14] Natl Hosp Org Shikoku Canc Ctr, Dept Gastrointestinal Med Oncol, Matsuyama, Ehime, Japan
[15] Tokai Cent Hosp, Kakamigahara, Gifu, Japan
[16] Yokohama City Univ, Dept Assoc Int Arts & Sci, Yokohama, Kanagawa, Japan
[17] Kyoto Univ, Grad Sch Med, Dept Biomed Stat & Bioinformat, Kyoto, Japan