Efficacy of SRT as Salvage Therapy in Patients With Brain Oligo-progression of EGFR-mutant Non-small Cell Lung Cancer After Failure of the Third-generation EGFR-TKIs

About 20%-40% of NSCLC patients develop intracranial metastases, and most clinical studies suggest that the survival of lung cancer patients will be significantly shortened once they develop intracranial metastases. EGFR tyrosine kinase inhibitors (EGFR-TKIs) remain the standard first-line therapy for patients with advanced EGFR-mutated NSCLC, including brain metastases(EGFR BMs). The survival rate of NSCLC patients with EGFR BMs was significantly improved compared with that of mutation-free patients. Third-generation EGFR-TKIs have unique advantages in the treatment of NSCLC BMs due to their improved blood-brain barrier permeability, and with the development of radiotherapy technology, stereotactic radiation therapy (SRT) has also demonstrated its remarkable qualities of high efficiency and low toxicity in a limited number of intracranial metastases. The clinical mechanisms of resistance to third-generation EGFR-TKIs are far more complex than those of first-generation TKIs, and the treatment paradigm for disease progression including intracranial progression is challenging. It would be interesting to design prospective clinical studies of patients with EGFR BMs treated with the third-generation TKIs followed by salvage SRT for oligo-progression. Therefore, the investigator designed this prospective, phase II clinical study of intracranial oligo-progression applied with stereotactic radiotherapy as salvage therapy in EGFR BMs patients after failure of the third-generation EGFR-TKIs.