Simple SummaryBrain metastases are the most frequent type of intracranial cancer. Although the prognosis has improved, the outcomes still vary widely, with a median survival of less than one year. The Recursive Partitioning Analysis (RPA) is one of the first proposed brain metastases prognostic tools. We hypothesized that an Updated RPA (U-RPA) prognostic index, which can easily be determined in the clinic, would be informative for both patients and clinicians to make decisions in the contemporary management of brain metastases. We report a retrospective analysis of all patients treated at three academic institutions, between 2017 and 2019, to compare outcomes based on the U-RPA and according to the type of treatment and primary cancer. Our results suggest that determination and documentation of the U-RPA at the time of diagnosis may assist patients and clinicians to make better-informed decisions based on the potential value of contemporary brain-directed treatment options.AbstractPatients with brain metastases (BMETS) need information about the prognosis and potential value of treatment options to make informed therapeutic decisions, but tools to predict survival in contemporary practice are scarce. We propose an Updated Recursive Partitioning Analysis (U-RPA) instrument to predict survival and benefit from brain-directed treatment (BDT) of contemporary patients. This was a retrospective analysis of patients with BMETS treated between 2017 and 2019. With survival as the primary endpoint, we calculated the U-RPA and generated estimates using Kaplan–Meier curves and hazard ratios. Of 862 eligible patients, 752 received BDT and 110 received best supportive care (BSC). Median overall survival with BDT and BSC was 9.3 and 1.3 months, respectively. Patients in RPA class 1, 2A, 2B and 3 who underwent BDT had median survival of 28.1, 14.7, 7.6 and 3.3 months, respectively. The median survival for patients in RPA 3 who received BDT (n= 147), WBRT (n= 79) and SRS (n= 54) was 3.3, 2.9 and 4.1 months, respectively. The U-RPA defines prognosis estimates, independent of tumor type and treatment modality, which can assist to make value-based care treatment decisions. The prognosis for patients in U-RPA class 2B and 3 remains poor, with consideration for early palliative care involvement in these cases.