Early or Delayed Intervention of Brain Radiotherapy Combined With Almonertinib in EGFR Mutated NSCLC With Brain Metastases

Inclusion Criteria: * Patients with histologically or cytologically confirmed non-small cell lung cancer; * Initial diagnosis of intracranial oligometastases (no treatment after brain metastases) was defined as brain parenchymal metastases confirmed by MRI, the number of intracranial parenchymal metastases was less than 5, and the lesions were 3mm away from the optic nerve and brainstem; There must be at least one measurable lesion with a diameter of 5mm or more in the brain. * EGFR sensitivity mutation (exon19del or exon21 L858R); * Anti-EGFR-targeting drugs and other TKI drugs have not been used in the past; * Age 18-75; Inclusion criteria: * A history (past or concurrent) of malignancies in other sites, excluding curable non-melanoma skin cancer and cervical carcinoma in situ; * The subjects had received brain radiotherapy before enrollment; * Patients whose lung lesions were surgically evaluated as resectable were not included if there was no metastasis in other parts of the body; * Received EGFR inhibitors (including small molecule or monoclonal antibody therapy) or systematic anti-tumor therapy before treatment; * Prior patients with interstitial lung disease, drug-induced interstitial disease, radiation pneumonia requiring hormone therapy, or any clinically proven active interstitial lung disease with idiopathic pulmonary fibrosis found on CT scan at baseline; * Pregnant and lactating patients; * MRI contraindicated patients; * Patients who cannot receive oral administration, need intravenous high-energy nutrition, have undergone previous surgery that interferes with absorption, or have active digestive tract ulcers; * The researchers judged that brain radiotherapy could not be received because of other head and facial diseases; * Any unstable systemic disease (including active infection, poorly controlled hypertension, unstable angina, congestive heart failure, liver, kidney or metabolic disease).