EGFR and leptomeningeal metastasis: Based on previous studies, patients without driver oncogenes have demonstrated a median overall survival of about 1.4 to 5.9 months from diagnosis.[1,2] Contrarily, for patients with NSCLC harboring driver oncogenes who develop meningeal carcinomatosis, molecularly targeted drugs, such as epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) and anaplastic lymphoma kinase (ALK) inhibitors, have been shown to be effective treatment options.[1–4] However, achieving long-term survival in patients with meningeal carcinomatosis resistant to these drugs is difficult.