Trial of Preoperative Radiosurgery Versus Postoperative Stereotactic Radiotherapy for Resectable Brain Metastases

Inclusion Criteria: 1. Provision of signed and dated informed consent form 2. Stated willingness to comply with all study procedures and availability for the duration of the study 3. Age ≥18 4. Karnofsky performance status ≥60 5. Histological diagnosis of a malignant primary or metastatic tumour 6. Ability to take steroids 7. No contraindication to magnetic resonance imaging (MRI) 8. MRI-diagnosis of a clearly demarcated contrast-enhancing brain metastasis up to 4.0 cm diameter indicated for neurosurgical resection (tumorboard decision). Up to 3 other brain metastases suitable for primary radiosurgery/ stereotactic radiotherapy 9. Survival estimated by primary clinician \> 12 months 10. Platelet count \> 100/ml, INR \< 1.3, Hb \> 7.5 g/dL Exclusion Criteria: 1. Radiosensitive histology: germ cell tumour, lymphoma, multiple myeloma 2. \>10 mm midline shift, effacement of the 4th ventricle or other sign of raised intracranial pressure requiring urgent decompressive surgery 3. More than 4 brain metastases or the diameter of the metastasis for resection \>4.0 cm. 4. More than 1 metastasis requiring resection 5. Leptomeningeal disease in the CSF or on MRI (unless localized and can be irradiated then resected with the metastasis) 6. Prior radiation to the brain (SRS/SRT to lesion to be resected and /or WBRT) 7. Prior resection of a primary or secondary brain tumor 8. Prior diagnosis of a non-meningioma brain tumor 9. Prior radionuclide therapy within 30 days 10. Prior anti-VEGF therapy within 6 weeks 11. Unable to tolerate radiosurgery immobilization and treatment 12. Inability to give informed consent 13. Pregnancy or lactation 14. Females of reproductive potential not willing to use effective contraception for at least 6 months after radiotherapy 15. Males of reproductive potential not effective contraception for 3 months after radiotherapy 16. Lack of likely compliance with protocol and follow-up