1. Division of Gastrointestinal Oncology, Shizuoka Cancer Center, 1007 Shimonagakubo, Nagaizumi-cho, Sunto-gun, Shizuoka 411-8777, Japan
2. Department of Gastroenterology & Hepatology, Hokkaido University Hospital, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan
3. Department of Surgery & Science, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka, 812-8582, Japan
4. Medical Affairs Division, Chugai Pharmaceutical Co., Ltd, 1-1 Nihonbashi-Muromachi 2-chome, Chuo-ku, Tokyo, 103-8324, Japan
5. P4 Statistics Co., Ltd, Todoroki, Setagaya-ku, Tokyo, 158-0082, Japan
6. Department of Biostatistics, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan