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

PATIENT CHARACTERISTICS: Age: 18 to 70 Performance status: WHO 0-2 Hematopoietic: WBC at least 4,000 Platelets at least 100,000 Hemoglobin normal (at least 6.8 mmoles/liter) Hepatic: Bilirubin no greater than 2 times normal Other liver function tests no greater than 2 times normal Renal: Creatinine no greater than 1.3 mg/dL (120 micromoles/liter) Creatinine clearance greater than 60 mL/min Other: No active, uncontrolled infection No requirement for antibiotics that might interfere with platinum excretion No requirement for drugs affecting bone marrow function (e.g., lithium, corticosteroids) No medical condition precluding postoperative chemotherapy No prior or concurrent malignancy other than nonmelanomatous skin cancer

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy Endocrine therapy: Not specified Radiotherapy: No prior locoregional radiotherapy to the head and neck Surgery: Excision with curative intent required