Adaptive dose painting appears to increase the chance of cure at minimized radiation-induced toxicity in intensity-modulated radiotherapy (IMRT) for primary head and neck cancer. This could also be of importance in IMRT for recurrent and second primary head and neck cancers in previously irradiated territory.

This trial investigates the feasibility of continuous adaptive 18F-Fluorodeoxyglucose-Positron Emission Tomography-voxel ([18F]FDG-PET-voxel) intensity-based IMRT in reirradiation of patients with recurrent and second primary head and neck cancer.

Inclusion Criteria:

• Histologically confirmed recurrences and second primary squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx or larynx in the previously irradiated territory.
• Primary unresectable tumor and/or patients refused surgery.
• No grade 3 or more late toxicity (except xerostomia) after the initial radio(chemo)therapy for primary head and neck cancer.
• Minimal interval 12 months after the initial radio(chemo)therapy for primary head and neck cancer.
• Decision of a multidisciplinary tumor board on curative radiotherapy (in combination or not with targeted therapy with cetuximab)
• Karnofsky performance status ≥70%.
• Age ≥ 18 years old.
• Informed consent obtained, signed and dated before specific protocol procedures.

Exclusion Criteria:

• Previous radiotherapy for cT1-2 cN0 M0 glottic cancer.
• Brachytherapy as treatment for second primary / recurrence.
• Distant metastases.
• Other second primary tumors that are not under control.
• Pregnant or lactating women.
• Elevated blood creatinine level.
• Allergy to the CT-contrast agents.
• Mental condition rendering the patient unable to understand the nature, scope, and possible consequences of the study.
• Patient unlikely to comply with protocol, i.e. uncooperative attitude, inability to return for follow-up visits, and unlikely to complete the study.