1. Histologically or cytologically proven non small cell lung cancer

2. New developed or progression of brain lesions among patients with good control of extracranial lesions to erlotinib

3. patients who are receiving erlotinib as salvage therapy

4. At least one unidimensionally measurable lesion with a diameter \> 10mm using brain MRI

5. at least on unidimensionally measurable or evaluable lesion

6. male or female patients aged \>18 years

7. ECOG performance status 0-2

8. Adequate hematologic function

9. adequate renal function

10. adequate hepatic function

The Continuation of Erlotinib