Gemcitabine and Carboplatin Followed By Docetaxel in Treating Patients With Stage IIIB or Stage IV Non-Small Cell Lung Cancer

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed non-small cell lung cancer (NSCLC) Stage IIIB with pleural effusion OR stage IV disease Recurrent disease after primary treatment with radiotherapy or surgery allowed Measurable disease or nonmeasurable disease Measurable disease, defined as at least 1 unidimensionally measurable lesion at least 20 mm by conventional techniques OR at least 10 mm by spiral CT scan Nonmeasurable disease, defined as all other lesions, including small lesions (longest diameter less than 20 mm by conventional techniques OR less than 10 mm by spiral CT scan) or any of the following: Bone lesions Leptomeningeal disease Ascites Pleural/pericardial effusion Inflammatory breast disease Lymphangitis cutis/pulmonis Cystic lesions Abdominal masses not confirmed and followed by imaging techniques No symptomatic CNS metastases Treated, stable CNS metastases allowed provided patient is not receiving radiotherapy or corticosteroids PATIENT CHARACTERISTICS: Age Over 18 Performance status ECOG 0-2 Life expectancy At least 12 weeks Hematopoietic WBC at least 3,000/mm^3 Absolute neutrophil count at least 1,000/mm^3 Platelet count at least 100,000/mm^3 Hepatic Bilirubin no greater than 1.5 mg/dL SGOT no greater than 3.0 times upper limit of normal (ULN) (less than 5.0 times ULN for patients with documented benign disease) Alkaline phosphatase less than 3.0 times ULN (for patients with documented benign disease) Renal Creatinine no greater than 1.5 mg/dL Other Not pregnant or nursing Fertile patients must use effective contraception during and for 3 months after study participation No active and ongoing infection No concurrent serious systemic disorder that would preclude study participation No other primary malignancy within the past 5 years except carcinoma in situ of the cervix, adequately treated basal cell skin cancer, or T1 vocal cord cancer in remission Other prior cancers unlikely to affect survival for the next 3 years (e.g., low-grade early stage prostate cancer) are allowed PRIOR CONCURRENT THERAPY: Biologic therapy No concurrent immunotherapy Chemotherapy No prior chemotherapy for NSCLC, including neoadjuvant and adjuvant therapy No other concurrent chemotherapy Endocrine therapy See Disease Characteristics No concurrent antitumor hormonal therapy (excluding contraceptives and replacement steroids) Radiotherapy See Disease Characteristics At least 3 weeks since prior radiotherapy and recovered Prior radiotherapy to less than 25% of bone marrow allowed provided the irradiated area is not the only site of measurable disease No concurrent radiotherapy Surgery See Disease Characteristics Other At least 3 weeks since prior therapy for cancer More than 4 weeks since prior investigational agents No other concurrent experimental medications No other concurrent therapy for cancer