1. Department of Otolaryngology - Head and Neck Surgery; Hokkaido University Graduate School of Medicine; Sapporo Japan
2. Head and Neck Surgery Division; National Cancer Center Hospital East; Kashiwa Japan
3. Department of Head and Neck Oncology, Cancer Institute Hospital; Japanese Foundation for Cancer Research; Tokyo Japan
4. Department of Otolaryngology, Head and Neck Surgery; Osaka Medical Center for Cancer and Cardiovascular Diseases; Osaka Japan
5. Department of Head and Neck Surgery; Hyogo Cancer Center; Kobe Japan
6. Department of Head and Neck Surgery; Aichi Cancer Center; Nagoya Japan
7. Department of Otolaryngology - Head and Neck Surgery; Kobe University Graduate School of Medicine; Kobe Japan
8. Department of Oto-Rhino-Laryngology; Jikei University School of Medicine; Tokyo Japan
9. Department of Otolaryngology - Head and Neck Surgery; Tohoku University Graduate School of Medicine; Sendai Japan
10. Department of Otolaryngology - Head and Neck Surgery; Iwate Medical University School of Medicine; Morioka Japan
11. Division of Head and Neck Surgery; Miyagi Cancer Center; Sendai Japan
12. Department of Otorhinolaryngology - Head and Neck Surgery; National Shikoku Cancer Center; Matsuyama Japan
13. Department of Otorhinolaryngology; National Tokyo Medical Center; Tokyo Japan