radiosurgery dose reduction for brain metastases on immunotherapy (radremi): a prospective pilot study

Conditions: Brain Tumor; Brain Metastases; Brain Cancer

Summary: this study will evaluate the rate of radiation necrosis following treatment with immune checkpoint inhibitor (ici) treatment and radiation therapy in subjects with metastatic brain cancer. subjects will be treated with the standard of care immunotherapy followed by radiation therapy via stereotactic radiosurgery at a reduced dose.

this is a prospective, single arm, pilot study to determine the symptomatic radiation necrosis rate at 6 months utilizing dose-reduced stereotactic radiosurgery with immunotherapy for subjects with a diagnosis of 1-10 brain metastases from mri and tissue diagnosis of primary malignancy. primary end-point is 6 month symptomatic radiation necrosis, defined as a 6-month rate of clinical symptomatology requiring steroid administration (i.e. decadron) and/or operative intervention concomitant with advanced and routine brain imaging findings consistent with radiation necrosis. follow-up mris will be fused with the planning scan for this assessment.

Eligibility criteria:
inclusion criteria: 1. brain mri-confirmed 1-10 solid tumor brain metastases 2. biopsy-confirmed primary malignancy 3. ds-gpa estimated median survival of at least 6 months, for histologies not included in the ds-gpa, publications or noted online at brainmetgpa.com, the pi will use either published or validated data or their best clinical judgment to determine the patient's expected survival 4. stereotactic radiosurgery candidate per treating radiation oncologist 5. ≥ 18 years old at the time of informed consent 6. ability to provide written informed consent and hipaa (health insurance portability and accountability act) authorization. 7. alc \> 800/ul (ku et al., 2010) 8. patients currently on cytotoxic chemotherapy are eligible 9. patients receiving ici up to 30 days prior to delivery of srs are eligible 10. patients having undergone operative resection for metastatic brain disease within 30 days of immune checkpoint inhibitor (ici) administration are eligible. 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.)

Keywords: radiation immune therapy stereotactic radiosurgery