The Study of Gemcitabine in the Maintenance Treatment of Advanced Non-small Cell Lung Cancer

Inclusion Criteria:

18~75 years Patients who were diagnosed by the histologic, cytologic diagnosis of IIIb-IV non-small cell lung cancer patients who have acceptted combination chemotherapy based on platinum 4 course,SD OR PR,the CR patients should accept 6 course of combination chemotherapy.

3~8 weeks after patients complete first line chemotherapy(include radiotherapy) Ecog0-2 Expected life time longer than 3 monthes

Normal laboratory values:

• leucocyte ≥ 4×109/L
• neutrophil ≥ 1.5×109/L
• platelet ≥ 100×109/L
• Hemoglobin ≥ 10g/L
• ALT and
• AST ≤ 2.5×ULN (≤ 5×ULN if liver metastasis) Signed written informed consent

Exclusion Criteria:

• Patients have used drugs according to protocol
• Uncontrolled infection of Bacterial or virus or fungal
• Patients with other malignant tumor
• Uncontrolled brain metastases
• Female patients during their pregnant and lactation period, or patients without contracep