1. Division of Medical Oncology, Department of Internal Medicine, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea;
2. Department of Thoracic and Cardiovascular Surgery, Yonsei University College of Medicine, Seoul, South Korea;
3. Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea;
4. Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea;
5. Department of Thoracic and Cardiovasular Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea;
6. Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea;