Combination Chemotherapy With or Without Radiation Therapy in Treating Patients With Stage IIIA Non-small Cell Lung Cancer

DISEASE CHARACTERISTICS: Histologically confirmed stage IIIA non-small cell lung cancer that has been completely resected by lobectomy, bilobectomy, pneumonectomy, or sleeve lobectomy through any incision (thoracoscopic or video assisted resection is acceptable) No known residual disease present Involvement in N2 nodes must have been determined only at the time of surgical exploration or by postoperative pathologic diagnosis All grossly involved nodes must be removed at surgery No positive mediastinoscopy (if lymph nodes on CT scan are greater than 1.5 cm in diameter, mediastinoscopy is required) PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ZUBROD 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 SGOT no greater than upper limit of normal Renal: Creatinine clearance at least 20 mL/min Other: Not pregnant or nursing PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent growth factors Chemotherapy: No prior chemotherapy for non-small cell lung cancer No other concurrent chemotherapy Endocrine therapy: No concurrent hormone therapy except: Steroids for adrenal failure Hormones for nondisease related conditions Dexamethasone as an antiemetic Radiation therapy: No prior radiotherapy for non-small cell lung cancer Surgery: See Disease Characteristics