[1] Natl Canc Ctr Hosp East, Dept Gastroenterol & Endoscopy, Kashiwa, Chiba, Japan
[2] Kitasato Univ, Sch Med, Dept Gastroenterol, Sagamihara, Kanagawa, Japan
[3] Saitama Canc Ctr, Dept Endoscopy, Ina, Saitama, Japan
[4] Ichinomiyanishi Hosp, Dept Gastroenterol, Ichinomiya, Aichi, Japan
[5] Natl Canc Ctr Hosp East, Dept Gastroenterol & Endoscopy, 6-5-1 Kashiwanoha, Kashiwa, Chiba 2778577, Japan