1. Department of Colorectal Surgery, National Cancer Center Hospital, Tokyo, Japan
2. Department of Gastroenterology and Gastrointestinal Oncology, National Cancer Center Hospital East, Tokyo, Japan
3. JCOG Data Center/Operations Office, National Cancer Center Hospital, Tokyo, Japan
4. Department of Gastroenterology, Saitama Medical University International Medical Center, Saitama, Japan
5. Clinical Oncology Division, Kochi Health Sciences Center, Kochi, Japan