1. Department of Gastroenterology, Otaru General Hospital, Otaru
2. Department of Hepatobiliary and Pancreatic Surgery, National Cancer Center Hospital East, Kashiwa
3. Department of Hepatobiliary and Pancreatic Oncology, National Cancer Center Hospital East, Kashiwa
4. JCOG Data Center/Operations Office, National Cancer Center Hospital, Tokyo
5. Department of Hepatobiliary and Pancreatic Oncology, National Cancer Center Hospital, Tokyo
6. Clinical Research Center, National Hospital Organization Shikoku Cancer Center, Matsuyama
7. Department of Medical Oncology, Kyorin University School of Medicine, Tokyo, Japan