RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. It is not yet known which regimen of chemotherapy is more effective for non-small cell lung cancer.

PURPOSE: Randomized phase III trial to compare the effectiveness of two regimens of chemotherapy in treating patients who have stage IIIB or stage IV non-small cell lung cancer.

OBJECTIVES: I. Compare gemcitabine plus vinorelbine vs standard chemotherapy containing cisplatin in terms of the effect on the quality of life of patients with stage IIIB or IV non-small cell lung cancer. II. Compare the effect of these regimens on the overall survival of these patients. III. Compare the toxic effects of these regimens in these patients. IV. Compare the effect of these regimens on the rate of objective response in these patients.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to center, stage of disease (IIIB vs IV), and performance status (0 vs 1 vs 2). Patients are randomized to one of two treatment arms. Arm I: Patients receive cisplatin IV on day 1 and either gemcitabine IV or vinorelbine IV on days 1 and 8. Arm II: Patients receive gemcitabine IV and vinorelbine IV on days 1 and 8. Treatment repeats every 21 days for up to 6 courses. Quality of life is assessed prior to therapy and before each course of chemotherapy to the fourth course.

PROJECTED ACCRUAL: A total of 500 patients will be accrued for this study.

DISEASE CHARACTERISTICS: Histologically or cytologically proven non-small cell lung cancer Stage IV OR Stage IIIB with supraclavicular lymph node metastases and/or pleural effusion that is not curable with radiotherapy Measurable or evaluable disease No CNS metastases

PATIENT CHARACTERISTICS: Age: Under 70 Performance status: ECOG 0-2 Life expectancy: Not specified Hematopoietic: Neutrophil count at least 2000/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 10 g/dL Hepatic: (Unless caused by liver metastases) Bilirubin no greater than 1.25 times upper limit of normal (ULN) SGOT or SGPT no greater than 1.25 times ULN Renal: Creatinine no greater than 1.25 times ULN Other: No prior or concurrent malignancy except basal or squamous cell skin cancer or carcinoma in situ of the cervix

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics Concurrent palliative radiotherapy allowed Surgery: Not specified