1. Division of Research and Development for Minimally Invasive TreatmentCancer CenterKeio University School Of MedicineTokyoJapan
2. Division of Gastroenterology and HepatologyDepartment of Internal MedicineKeio University School of MedicineTokyoJapan
3. Department of GastroenterologyNippon Medical SchoolTokyoJapan
4. Japan Council for Quality Health CareJapan