Gemcitabine Plus Carboplatin or Cisplatin in Treating Patients With Stage IIIB, Stage IV, or Recurrent Non-small Cell Lung Cancer

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed stage IIIB or IV non-small cell lung cancer (NSCLC) Recurrent NSCLC treated with radiation or surgery allowed Bidimensionally measurable disease by x-ray, CT scan, MRI, or physical exam outside of irradiation field No active CNS metastases PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 70-100% Life expectancy: At least 12 weeks Hematopoietic: WBC at least 3,500/mm3 Granulocyte count greater than 1,500/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 9 g/dL Hematocrit at least 30% Hepatic: Bilirubin no greater than 2 mg/dL PT or aPTT no greater than 1.5 times upper limit of normal (ULN) AST or ALT no greater than 3 times ULN (5 times ULN if liver metastases present) Renal: Creatinine no greater than 2 mg/dL Other: Not pregnant or nursing Fertile patients must use effective contraception during and for 3 months after study No serious concurrent systemic disorder that would preclude study compliance No active infection No second primary malignancy within the past 5 years, except: Adequately treated basal cell skin cancer Carcinoma in situ of the cervix PRIOR CONCURRENT THERAPY: Biologic therapy: At least 3 weeks since prior biologic therapy No concurrent immunotherapy Chemotherapy: No prior chemotherapy No other concurrent chemotherapy Endocrine therapy: At least 3 weeks since prior endocrine therapy No concurrent hormonal therapy (except contraceptives and replacement steroids) Radiotherapy: See Disease Characteristics At least 3 weeks since prior radiotherapy No concurrent radiotherapy Surgery: See Disease Characteristics Other: At least 4 weeks since other prior investigational drugs No other concurrent experimental drugs No concurrent interleukin-11 for patients with cardiac disease