The purpose of this study is to test whether an early metabolic response, measured by PET/CT scan after the first cycle of chemotherapy, is able to predict which patients with advanced NSCLC have a better prognosis.

Inclusion Criteria:

• Diagnosis of cytologically or histologically confirmed non-small cell lung cancer.
• Metastatic (stage IV, both M1A or M1B) or locally advanced (stage IIIB, with metastasis to supraclavicular nodes) according to TNM VII edition.
• Both patients at first diagnosis or those with disease recurrence after initial surgery are eligible.
• At least one target or non-target lesion according to RECIST revised version 1.1.
• Age > or = 18 years .
• ECOG PS 0-2.
• Life expectancy > 3 months.
• Signed informed consent.

Exclusion Criteria:

• Uncontrolled diabetes (glucose > 200 mg/dl
• EGFR mutation, for those patients who have had testing done. (EGFR test is not required for participation in the study, but may be conducted as part of normal clinical practice, and patients with EGFR mutation would not be candidate for first-line chemotherapy.)
• Any other malignancies within 5 years (except for adequately treated carcinoma in situ of the cervix or basal or squamous cell skin cancer or surgically resected prostate cancer with normal PSA).
• Pregnant or lactating females.
• Previous medical therapy for metastatic disease (prior surgery, radiation therapy are permitted, as well as adjuvant medical therapy completed at least 6 months prior to study entry).
• Any poorly controlled illness (including active infections, significant hepatic, renal, metabolic or cardiac disease, myocardial infarction within previous 12 months) that may, according to physician's judgement, interfere with the patient's ability to undergo chemotherapy and/or the examinations within the study protocol
• Inability to provide informed consent.