1. Departments of Otolaryngology, School of Medicine, Jichi Medical University, Tochigi, Japan
2. Department of Diagnostic Pathology, Jichi Medical University Hospital, Tochigi, Japan
3. Radiooncology, School of Medicine, Jichi Medical University, Tochigi, Japan
4. Medical Oncology, School of Medicine, Jichi Medical University, Tochigi, Japan