Radiosurgery Dose Reduction for Brain Metastases on Immunotherapy (RADREMI): A Prospective Pilot Study

Exclusion Criteria

• •1. Major medical illnesses or psychiatric impairments, which in the investigator's opinion will prevent administration or completion of the protocol therapy and/or interfere with follow-up
• •2. Patients unable to receive MRI Brain
• •3. Patients with more than 10 brain metastases on MRI Brain imaging
• •4. Any lesion \> 4 centimeter maximum diameter
• •5. Total volume of metastatic disease more than 30 cubic centimeters
• •6. Previous whole brain radiation therapy
• •7. For Cohort 1: Previous stereotactic radiosurgery where the 50% isodose line overlaps with current treatment field
• •8. For Cohort 2: Patients whose treatment will have a dose overlap within the target from prior treatments of 20% or greater
• •9. Already receiving chronic dexamethasone (chronic = \> 2 weeks) prior to SRS
• •10. Not a radiosurgical candidate per Radiation Oncology discretion
• •11. Existing autoimmune disease
• •12. Patients who have an unknown primary cancer
• •13. Histology not amenable for SRS (i.e. lymphoma). (Small Cell Lung Cancer IS amenable.)