1. Department of Head and Neck Surgery and Oncology The Netherlands Cancer Institute Amsterdam the Netherlands
2. Department of Head and Neck Surgical Oncology University Medical Center Utrecht, Utrecht University Utrecht the Netherlands
3. Department of Otolaryngology and Head and Neck Surgery Leiden University Medical Center, Leiden University Leiden the Netherlands
4. Department of Medical Oncology The Netherlands Cancer Institute Amsterdam the Netherlands
5. Department of Otorhinolaryngology – Head and Neck Surgery University Medical Center Utrecht, UMC Brain Centre Utrecht the Netherlands
6. Department of Radiation Oncology The Netherlands Cancer Institute Amsterdam the Netherlands
7. Institute of Biostatistics and Registry Research Brandenburg Medical School Theodor Fontane Neuruppin Germany
8. Department of Medical Oncology University Medical Center Utrecht, Utrecht University Utrecht the Netherlands