Cares for elderly patients with advanced non-small cell lung cancer(NSCLC) become one of the common clinical practices oncologist are now facing. So, we need to seek adequate regimens for them. Gemcitabine is well known to be one of active third generation agents in terms of both efficacy and tolerability. Gemcitabine alone have been recommended as first line treatment for elderly NSCLC patients, especially in the aspect of tolerability. However, gemcitabine alone is suggested to be suboptimal to control their disease. Therefore, we plan to make an optimal regimen containing gemcitabine for the elderly patients.

Inclusion Criteria:

• Histologically- or cytologically- confirmed Non-Small-Cell Lung Cancer Stage IIIB/IV
• No prior chemotherapy
• Existence of measurable disease. The measurable disease should not have been irradiated
• Life expectancy of more than 3 months
• Age ≥ 70 years
• Performance status (ECOG):1 or 2
• Adequate bone marrow function (Absolute neutrophil count >1500/mm^3, Platelet count>100000/mm^3, Hemoglobin>9gr/mm^3)
• Adequate liver (Bilirubin<2 times upper limit of normal and SGOT/SGPT<3 times upper limit of normal) and renal function (creatinine<1.5mg/dl)
• Informed consent

Exclusion Criteria:

• Psychiatric illness or social situation that would preclude study compliance.
• Other concurrent uncontrolled illness.
• Other invasive malignancy within the past 5 years except nonmelanoma skin cancer
• Currently/recently taken warfarin, phenprocoumon or phenytoin
• Hypersensitivity history to any drug