Since the discovery of EGFR gene mutation in non-small cell lung cancer patients in 2004, EGFR-targeted anti-cancer drugs have made remarkable progress over the past 20 years. Tyrosine kinase inhibitors (TKIs) targeting this genetic mutation have been established as standard therapy through the first generation (Iressa), second generation (Giotrif ·Vizimpro), and third generation (Tagrisso). Among them, Tagrisso is currently the only third-generation EGFR-TKI in the global market and has maintained its top position for more than five years without any competing drugs. The strength of Tagrisso is that it shows better effects than the first and second generations, especially in brain metastasis, which lung cancer pati