Carboplatin, Capecitabine, and Radiation Therapy in Treating Patients With Stage III or Stage IV Head and Neck Cancer

DISEASE CHARACTERISTICS: Histologically confirmed squamous cell carcinoma of the head and neck, including 1 of the following types: Oral cavity Oropharynx Hypopharynx Clinical stage III-IVB (T2-T4, N0-N3, M0) disease Measurable disease by physical exam, endoscopy, and/or CT scan or MRI Residual measurable disease after fine needle aspiration, core needle biopsy, or incisional or excisional biopsy of the primary tumor No evidence of distant metastases (M1) PATIENT CHARACTERISTICS: Age 18 and over Performance status Zubrod 0-1 Life expectancy Not specified Hematopoietic Absolute neutrophil count > 1,500/mm^3 Platelet count > 100,000/mm^3 Hemoglobin > 9 g/dL No uncontrolled coagulopathy Hepatic AST < 2 times normal Alkaline phosphatase < 2 times normal Bilirubin normal Renal Creatinine < 2.0 mg/dL OR Creatinine clearance > 50 mL/min Cardiovascular No congestive heart failure No symptomatic coronary artery disease No uncontrolled cardiac arrhythmias No myocardial infarction within the past year No other clinically significant cardiac disease Other Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for at least 30 days after completion of study treatment Nutritional and general physical condition must be compatible with proposed study treatment Mentally reliable No pre-existing peripheral neuropathy > grade 1 No history of hypersensitivity to fluorouracil, capecitabine, or carboplatin No active infection No other malignancy within the past 5 years except nonmelanoma skin cancer No major medical, psychiatric, or neurologic illness that would preclude study participation or giving informed consent PRIOR CONCURRENT THERAPY: Biologic therapy Not specified Chemotherapy More than 5 years since prior chemotherapy Endocrine therapy Not specified Radiotherapy No prior radiotherapy for head and neck tumor No prior radiotherapy to the region of planned study radiotherapy fields Surgery Recovered from prior surgery No unhealed surgical wounds Other More than 4 weeks since prior investigational drugs No concurrent warfarin, diphenylhydantoin, or fluconazole unless willing to undergo careful monitoring and appropriate dose adjustments