1. DAHANCA 16 Planned post-radiation neck dissection vs salvage neck dissection in patients with N2-3 SCC of the head and neck treated with primary radiotherapy DAHANCA.dk The Danish Head and Neck Cancer Study Group

2. Squamous cell carcinoma of oral cavity, oropharynx, hypopharynx, larynx T1-T4, N2N3 (unilat) M0 Candiate for primary RT±chemo Stratify: Institution Gender Site T- stage N- stage RANDOMIZERANDOMIZE DAHANCA 16 Radiotherapy followed by observation. Salvage neck dissection in case of recurrence Radiotherapy followed by planned neck dissection 6 weeks after completion of RT

3. DAHANCA 16 Endpoints: Primary:Persistent regional control (N-site) Secondary: Local control (T-site) Loco-regional control Disease-specific & overall survival CT-scan Side effects, QoL Statistics:Isolated N-failure improvement from 25% to 10% -> 60 events, 300 patients

4. Patient selection criteria: Histological proven SCC in the oral cavity, oropharynx, hypopharynx or larynx, TNM classification T1-T4, N2a, N2b, N2c contralateral or N3 unilateral, M0. Planned primary curative intended radiotherapy alone or combined chemo- radiotherapy No cervical lymph node metastases of squamous cell carcinoma from an unknown primary (CUP) Radiotherapy must start within 3 weeks after randomisation No prior treatment of the head and neck No previous or current malignancies affecting the current treatment, evaluation or outcome Absence of any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule; those conditions should be discussed with the patient before randomisation in the trial Age > 18 years WHO performance status 0-2 Written informed consent must be obtained and documented according to local and national regulations DAHANCA 16

5. Evaluation after the end of treatment: The first year: 1, 2, 5, 8 and 12 months after completion of radiotherapy. Second year: At least every four months From the third to the fifth year: At least every six months Quality of life (EORTC QLQ-C30 and HN35) 1, 2, 5, 8 and 12 months after completion of radiotherapy DAHANCA 16