Combination Chemotherapy and Computer-Planned Radiation Therapy in Treating Patients With Unresectable Stage III Non-Small Cell Lung Cancer

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed non-small cell lung cancer (NSCLC) * Squamous cell carcinoma * Adenocarcinoma, including bronchoalveolar cell carcinoma * Large cell anaplastic carcinoma, including giant and clear cell carcinoma * Inoperable stage IIIA or IIIB disease * No direct invasion of vertebral body * Tumors adjacent to a vertebral body without bone invasion allowed if all gross disease can be encompassed in radiotherapy boost field * Contralateral mediastinal disease (N3) allowed if all gross disease can be encompassed in radiotherapy boost field * No scalene, supraclavicular, or contralateral hilar node involvement * Transudate, cytologically negative, non-bloody pleural effusion allowed if it can be encompassed in radiotherapy field * No exudative, bloody, or cytologically malignant pleural effusion * Evidence of pleural effusion by chest CT scan but not chest x-ray that is too small to tap allowed * At least 1 unidimensionally measurable lesion * At least 20 mm by conventional techniques OR * At least 10 mm by spiral CT scan * The following are not considered measurable disease: * Bone lesions * Leptomeningeal disease * Ascites * Pleural/pericardial effusion * Abdominal masses that are not confirmed and followed by imaging techniques * Cystic lesions * Tumor lesions in a previously irradiated field PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * ECOG 0-1 Life expectancy: * Not specified Hematopoietic: * Granulocyte count at least 1,500/mm3 * Platelet count at least 100,000/mm3 Hepatic: * Bilirubin less than 1.5 mg/dL * AST less than 2 times upper limit of normal Renal: * Creatinine clearance 20-130 mL/min for females * Creatinine clearance 20-150 mL/min for males Pulmonary: * FEV1 at least 1.2 L Other: * Not pregnant or nursing * Fertile patients must use effective contraception * No other currently active malignancy (defined as completed prior therapy and considered to be at less than 30% risk of relapse) except non-melanoma skin cancer PRIOR CONCURRENT THERAPY: Biologic therapy: * Not specified Chemotherapy: * No prior chemotherapy for NSCLC * No other concurrent chemotherapy Endocrine therapy: * No concurrent hormonal therapy except steroids for adrenal failure or septic shock, hormones for non-disease-related conditions (e.g., insulin for diabetes), or glucocorticosteroids as antiemetics Radiotherapy: * See Disease Characteristics * No prior radiotherapy for NSCLC Surgery: * At least 2 weeks since prior exploratory thoracotomy