The primary aim of this study is to compare the change in neurocognitive outcome between baseline and 6 months for surviving patients in upfront WBRT versus SRS treatment groups. The primary study endpoint is neurocognitive function as measured by a significant change in online neurocognitive function (oNCF) z-score from baseline to 6 months. The outcomes will be compared after initial treatment and then repeatedly in follow-up, and will include the impact of salvage SRS treatments. This approach will allow us to assess the relative impact on neurocognitive outcomes of repeat SRS treatments to sites of new brain metastases.