1Department of Radiation Oncology, Yeungnam University College of Medicine, Daegu, Korea
2Department of Radiation Oncology, Samsung Medical Center,Sungkyunkwan University School of Medicine, Seoul, Korea
3Proton Therapy Center, Research Institute and Hospital, National Cancer Center, Goyang, Korea
4Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea
5Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
6Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
7Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea
8Department of Radiation Oncology, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
9Department of Medical Oncology, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
10Department of Radiation Oncology, Ajou University School of Medicine, Suwon, Korea
11Department of Radiation Oncology, Yeouido St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
12Department of Radiation Oncology, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea
13Department of Radiation Oncology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea