DISEASE CHARACTERISTICS: Histologically confirmed squamous cell carcinoma of the head and neck of the following sites: Oral cavity Oropharynx Hypopharynx (only if ineligible for protocol EORTC-24891) Larynx T3-4, any N, M0 or any T, N2-3, M0 disease (UICC staging) resected with curative intent T3, N0 carcinoma of the larynx with suitable microscopically clear margins is ineligible At least one of the following high-risk characteristics required: Histopathologically positive surgical margins No gross residual disease Perineural involvement Extranodal spread of disease Oral cavity or oropharyngeal lesions with metastatic nodes at level 4 or 5 Vascular embolisms in the neck No metastases at diagnosis No known CNS disease