1. Department of Otorhinolaryngology, Head and Neck SurgeryUniversity of Groningen, University Medical Center Groningen Groningen The Netherlands
2. Department of Otorhinolaryngology, Head and Neck SurgeryMedical Center Leeuwarden Leeuwarden The Netherlands
3. Department of EpidemiologyUniversity of Groningen, University Medical Center Groningen Groningen The Netherlands
4. Department of Research and DevelopmentNetherlands Comprehensive Cancer Organization (IKNL) Utrecht The Netherlands
5. Department of Laboratory MedicineUniversity of Groningen, University Medical Center Groningen Groningen The Netherlands
6. Department of RadiotherapyUniversity of Groningen, University Medical Center Groningen Groningen The Netherlands
7. Department of EndocrinologyUniversity of Groningen, University Medical Center Groningen Groningen The Netherlands