A comparison of biweekly combination chemotherapy (gemcitabine plus carboplatin) with weekly gemcitabine in elder patients (> 75) with previously untreated advanced non-small cell lung cancer. Primary objective is to determine the objective response rate (CR+PR by RECIST criteria) for biweekly gemcitabine and carboplatin combination chemotherapy versus weekly single gemcitabine as first-line therapy in elder advanced non-small lung cancer patients (> 76 years) who have received no prior treatment for non-small lung cancer. As secondary objectives, adverse event profile, tolerability of biweekly gemcitabine and carboplatin combination chemotherapy, progression-free survival and overall survival will be evaluated in both patients with biweekly gemcitabine and carboplatin combination chemotherapy and weekly single gemcitabine.

The study hypothesis is that biweekly combination chemotherapy of gemcitabine plus carboplatin may improve the efficacy.

Inclusion Criteria:

• Diagnosis of histologically confirmed stage IIIB or IV non-small cell lung cancer
• Good performance status (ECOG 0-1)
• No previous treatment
• Age 76 years and older
• Adequate bone marrow, liver and renal functions
• No pregnant
• Measurable disease, defined as at least one lesion whose longest diameter can be accurately measured as >=1.0 cm by spiral CT scan
• Provided written informed consent

Exclusion Criteria:

• Severe complications or a concomitant malignancy
• Prior and other concurrent radiotherapy, chemotherapy, immunotherapy, EGFR tyrosine kinase inhibitors
• Interstitial pneumonia or lung fibrosis
• Contraindicated gemcitabine or carboplatin
• Inappropriate patients for entry to this study, judged by the physicians