Osaka International Cancer Institute - Department of Gastrointestinal Oncology, Department of Gastrointestinal Oncology, Osaka International Cancer Institute, Kanazawa Medical Association, Department of Gastroenterology, Ishikawa Prefectural Central Hospital, Department of Endoscopy, Fukuoka University Chikushi Hospital, Department of Endoscopy, Fukuoka University Chikushi Hospital, Department of Gastroenterology, Kochi Red Cross Hospital, Department of Gastroenterology, Kochi Red Cross Hospital, Department of Gastrointestinal Oncology, Osaka International Cancer Institute, Department of Gastroenterology, Oita Red Cross Hospital, Department of Gastroenterology, Juntendo University, School of Medicine, Department of Gastroenterology, Juntendo University, School of Medicine, Wakayama Medical University - Clinical Study Support Centre and Department of Endoscopy, Fukuoka University Chikushi Hospital