Radiation Therapy With or Without Chemotherapy in Treating Patients With Head and Neck Cancer That Has Been Removed During Surgery

DISEASE CHARACTERISTICS: Biopsy-proven squamous cell carcinoma of one of the following sites: Hypopharynx Larynx Oral cavity Oropharynx At least 1 of the following high-risk factors required: Histologic extracapsular nodal extension Histologic involvement of 2 or more regional lymph nodes Microscopically positive mucosal margins Complete resection of all visible and palpable disease Therapy must begin within 8 weeks of tumor-related surgery Bilateral resections may or may not be performed simultaneously Eligibility window begins with first definitive surgery Neck dissection not required for T4 N0, truly midline supraglottic tumors No tumors of the lip, nasopharynx, or sinuses No synchronous or concurrent head and neck tumors No evidence of distant metastasis Concurrent registration on Fixed Tumor Repository Study allowed PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 60%-100% Hematopoietic: WBC at least 3,500 Platelets at least 100,000 Hepatic: Not specified Renal: Creatinine clearance greater than 50 mL/min Other: No medical contraindication to protocol therapy No second malignancy within 5 years No pregnant or nursing women PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy Endocrine therapy: Not specified Radiotherapy: No prior radiotherapy to head and neck region Surgery: See Disease Characteristics