Treatment of brain metastases in non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations: the role of EGFR tyrosine kinase inhibitors

The brain is one of the most common sites for lung adenocarcinoma metastasis, which are found in almost 20-30% of patients with the disease (1). These patients have poor median survival, and more effective therapies are urgently required. Since traditional chemotherapy is less effective against metastatic brain tumors, radiotherapy remains the main therapeutic or palliative option for inoperable central nervous system (CNS) disease. Radiotherapy supplemented with steroids has yielded responses rates of 50-75% for intracranial lesions, providing rapid attenuation of neurologic symptoms and improvement of performance status (2). However, brain metastases still herald a poor prognosis with a median survival of less than six months (3). Age, performance status, control of primary tumor, extend of extracranial disease, number of brain metastases, aggressive treatment modalities like surgery or radiosurgery, but also biomarkers such as expression levels of vascular enthothelial growth factor (VEGF), cyclooxygenase-2, epidermal growth factor receptor (EGFR) overexpression, and EGFR mutations have been explored as prognostic factors for patients with CNS metastases (4).