Sungkyunkwan University - Division of Hematology-Oncology, Seoul National University - Department of Internal Medicine, Yonsei University - Department of Internal Medicine, University of Ulsan - Department of Oncology, Ajou University - School of Medicine, National Cancer Center, Korea, Seoul National University - Department of Internal Medicine, Ewha Womans University, Gachon University - Department of Internal Medicine, Inha University - Department of Internal Medicine, Chung-Ang University, College of Medicine, Department of Internal Medicine, Sungkyunkwan University - Division of Hematology-Oncology, Yonsei University - Department of Internal Medicine, University of Ulsan - Department of Hematology and Oncology, Sungkyunkwan University - Division of Hematology-Oncology, Seoul National University - Department of Internal Medicine, Yonsei University - Yonsei Cancer Center, University of Ulsan - Department of Oncology, Sungkyunkwan University - Division of Hematology-Oncology, Sungkyunkwan University - Division of Hematology-Oncology and Seoul National University - Department of Internal Medicine