Early Prophylactic Versus Late Salvage Recombinant Human Endostatin in Managing Radiosurgery-Induced Brain Injury for NSCLC Brain Metastases.

Inclusion Criteria 1. Karnofsky performance status (KPS) score ≥60. 2. Histologically or cytologically confirmed non-small cell lung cancer (NSCLC). 3. Baseline contrast-enhanced brain MRI confirms 1-15 brain metastases, with a total volume of all lesions \<15 mL, and the largest lesion with a maximum diameter ≤4.0 cm or volume ≤10 mL. 4. Cohort A: Planned to receive SRS, and baseline MRI shows significant peritumoral edema (edema index \>2), where EI = (tumor volume + edema volume) / tumor volume. Cohort B: Radiographic (MRI) evidence of radiation-induced brain edema/necrosis after SRS (usually ≥3 months after SRS). 5. Prior or concurrent radiotherapy for extracranial lesions is allowed. Prior TKI, chemotherapy, or immunotherapy is allowed. After enrollment, systemic therapy may be continued or adjusted according to clinical need. 6. Within 14 days before study treatment, bone marrow and major organ function must meet the following criteria: ANC ≥1.5×10\^9/L; platelets ≥100×10\^9/L; hemoglobin ≥90 g/L; total bilirubin ≤1.5×ULN; AST and ALT ≤1.5×ULN; serum creatinine ≤1.5×ULN or CrCl ≥45 mL/min; INR ≤1.5; APTT ≤1.5×ULN; urine protein \<2+; if urine protein ≥2+, 24-hour urine protein \<2 g. 7. Female patients of childbearing potential must have a negative serum pregnancy test within 7 days before enrollment. All patients of reproductive potential must agree to use highly effective contraception during the study and for 6 months after the last dose. 8. Patients voluntarily participate, have signed the written informed consent form (ICF), and are expected to comply with and follow all study requirements. Exclusion Criteria 1. Known allergy to Endostar or any of its excipients. 2. Received any other anti-angiogenic therapy within 4 weeks before the first dose. 3. Uncontrolled hypertension despite medication (SBP \>150 mmHg and/or DBP \>100 mmHg). 4. History of major bleeding (e.g., hemoptysis, gastrointestinal bleeding) or current active bleeding, bleeding tendency, or coagulation disorder. 5. History of arterial thromboembolic events (e.g., MI, unstable angina, CVA, or TIA) within 6 months before the first dose. 6. Symptomatic CHF (NYHA Class ≥ II) or severe arrhythmia requiring treatment. 7. Severe hepatic/renal insufficiency: total bilirubin \>1.5×ULN; or ALT/AST \>2.5×ULN; or serum creatinine \>1.5×ULN and CrCl \<45 mL/min. 8. Urine protein ≥++, or 24-hour urine protein ≥2.0 g. 9. History of gastrointestinal perforation, active gastrointestinal bleeding, intra-abdominal abscess, or active IBD. 10. Symptomatic uncontrolled brain metastasis hemorrhage or obvious intracranial hypertension crisis, as judged by the investigator. 11. Contraindications to MRI. 12. Pregnant or lactating women. 13. Any severe acute/chronic medical condition, psychiatric disorder, or laboratory abnormality that may increase risk, interfere with results, or affect the investigator's judgment of the patient's ability to complete the study. 14. Poor compliance, and the patient is not expected to complete all necessary treatment and follow-up assessments.