1. Department of Head and Neck Surgical Oncology University Medical Center Utrecht Utrecht The Netherlands
2. Department of Medical Oncology University Medical Center Utrecht Utrecht The Netherlands
3. Department of Radiation oncology University Medical Center Utrecht Utrecht The Netherlands
4. Department of Pathology University Medical Center Utrecht Utrecht The Netherlands
5. Department of Research Comprehensive Cancer Center The Netherlands (IKNL) Utrecht The Netherlands
6. Department of Epidemiology University Medical Center Groningen Groningen The Netherlands