This is a single centre prospective exploratory study of effects of radiation therapy on biomarker development in patients with newly diagnosed (head and neck squamous cell carcinoma) HNSCC receiving curative therapy. This research is part 2 of the HN-BIO study.

This study will recruit up to 40 patients planned to receive curative (chemo) radiotherapy for (head and neck squamous cell carcinoma) HNSCC with primary tumor and/or involved lymph node suitable for repeat biopsy in clinic. After being informed about the study and potential risks, patients giving written informed consent will be randomized to receive conventional radiotherapy (single integrated boost or conventional two-phase at clinician discretion) or reversed two-phase treatment with delayed irradiation of elective nodal volumes. Patients will not be informed of their randomization result. Patients in both arms will undergo a baseline functional magnetic resonance imaging (fMRI) scan and within 72 hours, when possible, a biopsy of the primary tumor +/- lymph node will be performed in an out-patient clinic. If a suitable biopsy has been recently performed as part of diagnostic work up the baseline biopsy on study will be omitted when possible. In week 2 of radiotherapy, patients will have a second fMRI scan and a paired biopsy within 72 hours of the scan, where possible. A further optional biopsy and paired fMRI scan in week 4 will be considered for patients who are tolerating therapy without \>G1 toxicities. 16-24 hours prior to each biopsy the patient will take oral pimonidazole. At the time of each biopsy a blood draw will be performed.