[1] Natl Canc Ctr, Dept Gastrointestinal Med Oncol, Tokyo, Japan
[2] Natl Canc Ctr, Dept Esophageal Surg, Tokyo, Japan
[3] Natl Canc Ctr Hosp East, Dept Gastrointestinal Oncol, Kashiwa, Chiba, Japan
[4] Saitama Canc Ctr, Dept Gastroenterol, Saitama, Japan
[5] Aichi Canc Ctr Hosp, Dept Surg Gastroenterol, Nagoya, Aichi, Japan
[6] Shizuoka Canc Ctr, Div Esophageal Surg, Shizuoka, Japan
[7] Inst Stat Math, Res Ctr Med & Hlth Data Sci, Tachikawa, Tokyo, Japan
[8] Keio Univ, Dept Surg, Sch Med, Tokyo, Japan