Inclusion Criteria:

- Histologically confirmed non-small cell lung cancer with synchronous brain metastases
(diagnosis of brain lesion before or within 2 months from diagnosis of the primary
site tumor)

- One to 4 intraparenchymal brain metastases by contrast-enhanced MRI, meeting the
following criteria:

1. Well circumscribed tumor(s) with brain edema Grade 0-1

2. Maximum diameter ≤ 3.0 cm

- No prior complete resection of all known brain metastases or RT ④ No
leptomeningeal metastases by MRI or cerebrospinal fluid evaluation

- Patients without any symptoms or signs from brain metastases
(RTOG neurologic functions status of 0) ⑥ Age, 18 and over ⑦
ECOG performance status 0-1 ⑧ Written informed consent

Exclusion Criteria:

- severe co-morbid illness and/or active infections ② pregnant or lactating women

- RTOG neurologic function status of 1~4 ④ Uncontrollable extracranial metastases