[1] Natl Canc Ctr Hosp East, Gastroenterol & Gastrointestinal Oncol, Kashiwa, Chiba, Japan
[2] Univ Milan, Niguarda Canc Ctr, Milan, Italy
[3] Daiichi Sankyo Inc, Med, Basking Ridge, NJ USA
[4] Daiichi Sankyo Co Ltd, Biostat & Data Management Dept, Chuo Ku, Tokyo, Japan
[5] Daiichi Sankyo Co Ltd, Clin Dev, Chuo Ku, Tokyo, Japan
[6] Mayo Clin, Canc Ctr, Dept Med Oncol, Rochester, MN USA