FDG-PET Scan Response Guided Chemotherapy Strategy for Advanced Non-small Cell Lung Cancer

Inclusion Criteria: 1. Histologically confirmed non-small cell carcinoma. 2. Stage IIIB (wet) or IV advanced NSCLC. 3. No evidence of prior malignancies for 3 years except treated basal cell or squamous cell carcinoma of skin and carcinoma in situ of uterine cervix. 4. Measurable disease by RECIST criteria. 5. Adequate organ function as follows. * Seum AST/ALT \< 2.5 x Upper normal limit (UNL) (if hepatic metastasis \< 5 x UNL) * Total bilirubin \< 1.5 x UNL * Serum creatinine \< 1.5 mg/dL * Absolute neutrophil count \> 1500/uL * Platelet \> 100,000/uL * Hemoglobin \> 9.0 g/dL 6. ECOG Performance status 0-1 7 Age \> 18 8\. If previously treated with major surgery, it should be over at least 4 weeks. And if previously treated with radiotherapy, it should be over at least 2 weeks. 9\. Written consent Exclusion Criteria: 1. Previous chemotherapy. 2. Symptomatic brain metastasis. 3. Concurrent severe medical illness. 4. Pregnancy and lactation. 5. If there are findings which may increase risk with chemotherapy or inhibit to analyze the result of clinical trial. * Uncontrolled diabetes mellitus.