1. Department of Radiation Oncology Seoul National University College of Medicine Seoul Korea
2. Cancer Research Institute Seoul National University College of Medicine Seoul Korea
3. Medical Research Center, Institute of Radiation Medicine Seoul National University Seoul Korea
4. Department of Surgery Seoul National University College of Medicine Seoul Korea
5. Department of Otorhinolaryngology Seoul National University College of Medicine Seoul Korea
6. Department of Internal Medicine Seoul National University College of Medicine Seoul Korea
7. Department of Internal Medicine Chungang University Gwangmyeong Hospital Gyeong‐gi Korea