1. Department of Surgery, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea.
2. Epidemiology and Biostatistics Office, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea.
3. Department of Medical Oncology, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea.
4. Department of Radiation Oncology, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea.
5. Department of Diagnostic Radiology, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea.
6. Department of Pathology, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea.