1. Department of Otorhinolaryngology & Head & Neck Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
2. Department of Internal Medicine IV, University Medical Center Halle (Saale), Germany
3. Department of Medical Biometry & Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
4. Department of Medical Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany