[1] Toyoshima Endoscopy Clin, Gastroenterol, Tokyo, Japan
[2] Keio Univ, Canc Ctr, Div Res & Dev Minimally Invas Treatment, Sch Med, Tokyo, Japan
[3] Keio Univ, Dept Internal Med, Div Gastroenterol & Hepatol, Sch Med, Tokyo, Japan
[4] Keio Univ, Med Educ Ctr, Sch Med, Tokyo, Japan
[5] Asahi Life Fdn, Inst Adult Dis, Div Gastroenterol, Tokyo, Japan
[6] Univ Tokyo, Dept Gastrointestinal Surg, Tokyo, Japan
[7] Univ Tokyo, Grad Sch Med, Dept Gastroenterol, Tokyo, Japan
[8] Univ Tokyo, Dept Surg Oncol, Tokyo, Japan
[9] Fratern Mem Hosp, Dept Surg, Tokyo, Japan