1. Department of Medical Oncology, Ioannina University Hospital, Ioannina 45500, Greece
2. ENT Department, “AHEPA” Hospital, Aristotle University of Thessaloniki School of Medicine, Thessaloniki 57100, Greece
3. Siemens Healthcare Diagnostics, Cologne, Germany
4. Hellenic Cooperative Oncology Group, Data Office, Athens 45118, Greece
5. Department of Medical Oncology, “Papageorgiou” Hospital, Aristotle University of Thessaloniki School of Medicine, Thessaloniki 57100, Greece