1. Department of Radiation Oncology ChungBuk National University Hospital Chungcheongbuk‐do Republic of Korea
2. Department of Radiation Oncology Seoul National University Hospital Seoul Republic of Korea
3. Department of Radiation Oncology Cancer Research Institute, Seoul National University College of Medicine Seoul Republic of Korea
4. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine Seoul National University Hospital Seoul Republic of Korea
5. Department of Thoracic and Cardiovascular Surgery Seoul National University Hospital Seoul Republic of Korea