1. Department of Head and Neck Surgical Oncology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
2. Department of Radiation Oncology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
3. Radiation Oncology Division, Department of Diagnostic Imaging, Radiation Oncology and Hematology, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, Largo Agostino Gemelli 8, 00168 Rome, Italy
4. Otolaryngology Division, Azienda Ospedaliero Universitaria Sassari, Viale S. Pietro 43, 07100 Sassari, Italy
5. Department of Medicine, Surgery and Pharmacy, University of Sassari, Viale S. Pietro 43, 07100 Sassari, Italy
6. Otolaryngology Division, Department of Neurosciences, Sensory Organs and Thorax, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, Largo Agostino Gemelli 8, 00168 Rome, Italy
7. Department of Radiation Oncology, Mater Olbia Hospital, SS 125 Orientale Sarda, 07026 Olbia, Italy
8. Department of Otolaryngology-Head and Neck Surgery, IRCCS Istituto Nazionale dei Tumori (INT), 20133 Milan, Italy