Limertinib Plus Radiotherapy for EGFR-Mutant NSCLC With Brain Metastases

Inclusion Criteria: Patients must voluntarily agree to participate in this study and sign a written informed consent form. Patients aged 18-75 years. Patients must have histologically or cytologically confirmed advanced non-small cell lung cancer (NSCLC), staged as IV according to the 9th edition of the American Joint Committee on Cancer (AJCC) TNM staging system. Histological or cytological reports issued by nationally accredited hospitals or third-party testing institutions confirming the presence of EGFR classical mutations (19Del \& 21L858R). ECOG PS score of 0-1, and an estimated survival of ≥3 months, as determined by the investigator. Brain metastases (meningeal/parenchymal) confirmed by CT or MRI, with or without symptoms. Patients must have at least one measurable lesion according to RECIST 1.1 criteria. ≥3 primary brain lesions, with at least one lesion ≥2 cm. Patients must not have received any prior systemic anti-cancer treatment for advanced/metastatic non-small cell lung cancer, including standard chemotherapy, biological therapy, targeted therapy, immunotherapy, or investigational drug therapy. Patients who have received adjuvant or neoadjuvant therapy (chemotherapy and/or radiotherapy) are eligible if no disease progression occurred within 6 months after completion of treatment. Patients who have received local treatment (radiotherapy or pleural perfusion therapy) are also eligible if the treated lesions are not target lesions. Patients must meet the f…