Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea. Electronic address: yooc@amc.seoul.kr. Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea. Division of Oncology, Department of Internal Medicine, Haeundae Paik Hospital, Inje University College of Medicine, Busan, South Korea. Division of Hematology and Oncology, Department of Internal Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Seoul, South Korea. Department of Oncology/Hematology, Kyungpook National University Hospital, Kyungpook National University, Daegu, South Korea. Division of Hematology and Oncology, Department of Internal Medicine, Chungnam National University Hospital, Chungnam National University College of Medicine, Daejeon, South Korea. Clinical Research Center, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, South Korea; Department of Clinical Epidemiology and Biostatistics, University of Ulsan College of Medicine, Seoul, South Korea. Asan Image Metrics, Clinical Research Center, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, South Korea. Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA; Department of Medicine, Weill Medical College at Cornell University, New York, NY, USA.