Inclusion Criteria:

1. Age >18

2. Histologically or pathologically proven non-small cell lung cancer (NSCLC)

3. Leptomeningeal carcinomatosis confirmed by CSF cytology

4. A patients with EGFR mutation (including exon 19 deletion, L858R)

5. ECOG performance status 0-3

6. Expected life time more than at least 4 weeks

7. A patients who signed the informed consent prior to the participation in the study

8. Chemotherapy-naïve patient is eligible

9. Previous EGFR TKI is allowed if this drug was not specifically used for CNS
metastases

Exclusion Criteria:

1. A pregnant or lactating patient

2. A patient of childbearing potential without being tested for pregnancy at baseline or
with a positive test. (A postmenopausal woman with the amenorrhea period of at least
12 months or longer is considered to have non-childbearing potential.)

3. A man or woman of childbearing potential without the willingness to use a
contraceptive measures during the study

4. A patient with history of another malignant disease within past 3 years, except
curatively treated basal cell carcinoma of the skin, cervical carcinoma in situ, and
early gastric cancer

5. A patient with active interstitial lung disease, except simple lymphangitic lung
metastasis

6. A patient with history of allergic reaction to gefitinib or erlotinib

7. The following laboratory test results:

- Number of absolute neutrophils counts (ANC) < 1.0ⅹ109/L

- Number of platelets < 50 ⅹ109/L

- AST, ALT > 2.5 ⅹupper limit of normal

- Total bilirubin > 1.5 ⅹupper limit of normal

- Serum creatinine > 1.5 ⅹupper limit of normal

8. A patient with serious disease as followings

- Uncontrolled cardiac arrhythmia

- History of myocardial infarction within 6 months prior to the initiation of
study

- Neurological or psychiatric disorder including dementia or uncontrolled seizure

9. A patient who refused to sign the informed consent