1. Department of Radiation Oncology, Baskent University Medical Faculty, Adana, Turkey
2. Clinics of Otolaryngology, Adana City Hospital, Adana, Turkey
3. Department of Medical Oncology, Baskent University Medical Faculty, Adana, Turkey
4. Department of Radiation Oncology, Koc University, School of Medicine, Istanbul, Turkey
5. Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, TX, USA