EGFR and leptomeningeal metastasis: In patients with EGFR mutation-positive NSCLC who develop meningeal carcinomatosis, osimertinib has been reported to be the most beneficial treatment option.[3] Several studies have also shown that osimertinib has greater CNS penetration and higher brain exposure than other EGFR-TKIs.[10] These results indicate that CNS penetration is an important factor in the treatment of meningeal carcinomatosis with molecularly targeted drugs.