All patients will undergo a dedicated FDG PET/CT protocol 12 weeks after the end of chemoradiation (primary endpoint). In PET/CT negative patients, 2 monthly control visits will be performed complemented with additional imaging as required. All patients will undergo PET/CT 1 year after completing chemoradiation unless recurrent/residual disease was already proven pathologically. Patients with a PET/CT suspected for residual nodal disease must have pathological proof of nodal involvement (fine needle aspiration in non-operable patients or neck dissection in the others) before salvage chemotherapy is started.