Inclusion Criteria:  Histologically or cytologically verified invasive squamous cell carcinoma of the head and neck region; Sinonasal, oral cavity, hypopharynx cancer, larynx cancer, HPV-unrelated (p16 negative and/or HPV DNA negative) oropharyngeal cancer and TNM (primary tumor, regional nodes, metastasis) stage T4 any N M0 HPV-related (p16 positive and/or HPV DNA positive) oropharyngeal cancer.  Patients planned for standard curative treatment (radical radiotherapy with or without concomitant chemotherapy, with or without nimorazole hypoxic cell radiosensitizer) Planned treatment at the Oslo University Hospital Age > 18 years WHO (World Health Organization) performance status 0-2  Exclusion Criteria:  TNM (primary tumor, regional nodes, metastasis) stage cT1 cN0-N1 cM0 Glottic cancer cT1-T2 cN0 cM0 HPV-related oropharyngeal carcinoma cT1-T3 (any N) Cancer in the soft palate Diabetes mellitus Use of anticoagulant (or platelet inhibitor) Active smoking and/or alcohol abuse