This study is an open-label, randomized, Phase III trial designed to ascertain whether fractionated stereotactic radiosurgery (FSRS) results in lower incidence of Grade 2 or higher adverse radiation effect (ARE) by 9 months compared to single fraction stereotactic radiosurgery (SSRS) in patients with large brain metastases who have received or will receive immune checkpoint inhibitor (ICI) targeted to the PD-1/PD-L1 axis within 30 days of stereotactic radiosurgery (SRS). Participants will be randomized 1:1 to either SSRS or FSRS, using a minimization randomization strategy considering 4 prognostic factors of interest: radiosurgery platform (gamma knife vs. LINAC), timing of immunotherapy relative to radiation (ICI within 30 days prior to Day 1 of SRS or not), and surgical status (any resection cavity vs intact metastases only), and predominant tumor type (Melanoma vs. all others).
This study is designed to see if we can lower the chance of side effects from radiation in patients with breast, kidney, non-small cell lung cancer or melanoma that has spread to the brain and who are also being treated with immunotherapy, specifically immune checkpoint inhibitor (ICI) therapy. This study will compare the usual care treatment of single fraction stereotactic radiosurgery (SSRS) given on one day versus fractionated stereotactic radiosurgery (FSRS), which is a lower dose of radiation given over a few days to determine if FSRS is better or worse at reducing side effects than usual care treatment.