1Division of Medical Oncology, Department of Internal Medicine, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Korea
2Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
3Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
4Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, KOREA
5Division of Hematology-Oncology, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
6Department of Internal Medicine, Dong-A University Hospital, Dong-A University College of Medicine, Busan, Korea
7Division of Hematology-Oncology, Department of Internal Medicine, Kyungpook National University Hospital, Kyungpook National University School of Medicine, Daegu, Korea