1. Head and Neck Oncology and Surgery International University of Health and Welfare, Mita Hospital Tokyo Japan
2. Department of Head and Neck Surgery National Cancer Center Hospital Tokyo Japan
3. Department of Otorhinolaryngology, Head and Neck Surgery Yokohama City University, School of Medicine Yokohama Japan
4. Department of Otorhinolaryngology, Head and Neck Surgery Nagoya City University Graduate School of Medical Sciences Nagoya Japan
5. Department of Otolaryngology Head and Neck Surgery, Faculty of Medicine and Graduate School of Medicine Hokkaido University Sapporo Japan
6. Department of Otorhinolaryngology, Head and Neck Surgery Tokyo Medical University Tokyo Japan
7. Department of Otorhinolaryngology Head and Neck Surgery Keio University School of Medicine Tokyo Japan
8. Department of Otolaryngology Head and Neck Surgery Tokai University School of Medicine Isehara Japan
9. Department of Head and Neck Surgery Niigata Cancer Center Hospital Niigata Japan
10. Department of Otorhinolaryngology, Head and Neck Surgery Tokyo Medical University Hachioji Medical Center Tokyo Japan
11. Department of Otolaryngology, Head and Neck Surgery Chiba University Graduate School of Medicine Chiba Japan
12. Otorhinolaryngology, Head and Neck Surgery International University of Health and Welfare, Narita Hospital Chiba Japan
13. Department of Otorhinolaryngology, Head and Neck Surgery Kitasato University School of Medicine Kanagawa Japan
14. Department of Anatomic Pathology Tokyo Medical University Tokyo Japan