1. Department of Gastrointestinal Oncology Shizuoka Cancer Center Shizuoka Japan
2. Department of Clinical Oncology Aichi Cancer Center Hospital Nagoya Japan
3. Division of Cancer Center Hokkaido University Hospital Sapporo Japan
4. Department of Biostatistics Yokohama City University Yokohama Japan
5. Department of Gastroenterology and Hepatology Hokkaido University Hospital Sapporo Japan
6. Department of Medical Oncology Kushiro Rosai Hospital Kushiro Japan