FSRT Combines With Bevacizumab for Multiple Brain Metastases in Lung Adenocarcinoma

Inclusion Criteria: * Age ≥ 18 years old; * Cellular or histopathological confirmation of lung adenocarcinoma; * Prior to enrollment, brain enhanced magnetic resonance imaging shows (1) 1-2 brain metastases, with at least one measuring ≥3 cm in diameter; or (2) 3-10 brain metastases, with at least one measuring ≥2 cm in diameter; or (3) 11-20 brain metastases; and deemed unsuitable for single-session SRS by radiation oncologists; * At the time of enrollment, the extracranial disease status is stable; * Eastern Cooperative Oncology Group (ECOG) physical fitness status score 0-2 points * Normal liver, kidney, and bone marrow function within 14 days prior to enrollment: peripheral blood white blood cell count ≥ 4 × 10\^9/L; neutrophil count ≥ 1.5 × 10\^9/L, platelet count ≥ 100 × 10\^9/L, hemoglobin ≥ 100g/L, serum creatinine\<1.5 times the upper limit of normal values; Bilirubin\<1.5 times the upper limit of normal value; Transaminase\<2 times the upper limit of normal value; * The patient and their family agree and sign an informed consent form. Exclusion Criteria: * There are contraindications for bevacizumab, such as a history of cardiac and/or thromboembolic events, or uncontrolled hypertension; * Meningeal metastasis or extensive intracranial metastasis are not suitable for FSRT; * Bleeding tendency or coagulation dysfunction; * Patients with hemoptysis (≥ 1/2 teaspoon of fresh blood per day) within the past month; * Use full dose anticoagulant therapy within the past month; * Has experienced severe vascular disease in the past 6 months; * Have experienced gastrointestinal fistula, perforation, or abdominal abscess within the past 6 months; * Has experienced hypertensive crisis, hypertensive encephalopathy, symptomatic heart failure (New York Class II or above), acute myocardial infarction, cerebral infarction, cerebral parenchymal hemorrhage, or other active cerebrovascular or cardiovascular diseases within the past 6 months; * Patients with a history of arterial aneurysm or arteriovenous malformation; * Having undergone major surgery within 28 days, or minor surgery or needle biopsy within 48 hours; * Urinary protein 3-4+, or 24-hour urinary protein quantification\>1g; * Simultaneously accompanied by serious and uncontrolled other diseases.