1Department of Radiation Oncology, Ajou University Hospital, Suwon, Korea. 2Division of Gastroenterology, Department of Internal Medicine,Ajou University Hospital, Suwon, Korea. chunm@madang.ajou.ac.kr 3Division of Hematology-Oncology, Department of Internal Medicine,University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Korea.