Inclusion Criteria:  All patients older than 18 years with diagnosed HNSCC, attending the Department of Radiooncology and Radiotherapy or the Department of Oral and Maxillofacial Surgery at Charité for a treatment with curative intension ( R(C)T or primary surgery / combined). All patients received as pretherapeutic diagnostic method a 18F-Fluorodesoxyglucose (FDG) positron emission tomography (PET) imaging  Exclusion Criteria:  Patients with HNSCC who cannot be treated in a curative approach Patients with HNSCC treated in a curative approach but unable to receive FDG PET imaging before start of treatment Data from patients who have withdrawn their study consent