Abstract BACKGROUND Brain metastases (BM) significantly impact quality of life and survival in patients with metastatic renal cell cancer (mRCC). Based on the International Metastatic RCC Database Consortium (IMDC) risk classification, treatment strategies for patients with mRCC vary from systemic treatment with vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKIs) and/or immune checkpoint inhibitors (ICIs) to active surveillance (AS). Here, we describe the impact of treatment strategies on survival in patients with RCC and BM. METHODS We conducted a single-center, retrospective cohort study at Erasmus MC Cancer Institute (Rotterdam, Netherlands). All consecutive patients with RCC BM between 2011-2022 were included. Primary outcome was the BM-free survival, i.e. the time between diagnosis of extracranial metastases (ECM) and BM. Secondary outcome was overall survival (OS). RESULTS 46 patients with RCC BM were included: 25 (54.3%) had received prior systemic treatment for ECM, and 21 (45.7%) were treatment naive at diagnosis of BM. IMDC scores (favorable 12% resp. 0%, intermediate 48% resp. 64%, poor 24% resp. 0%, unknown 16% resp. 36%) were not significantly different (p=0.07) between these groups. In 39 (84.8%) of 46 patients, BM were metachronous ( >1 month) after ECM. In these patients (n=39), the median BM-free survival was 22.3 (IQR 5.7-46.7) months and was significantly longer (p=0.02) in previously treated patients (29.0 [IQR 12.6-57.0] months) as compared to treatment naive patients (6.8 [IQR 1.0-7.0] months). However, median OS since ECM diagnosis (39.1 [IQR 16.5-111.5] months) was not significantly different (p=0.62) between previously treated and treatment naive patients. CONCLUSION Patients with RCC who received systemic treatment for ECM prior to BM diagnosis, had a longer BM-free survival as compared to patients without previous systemic treatment. These results emphasize the need for careful evaluation of AS in patients with mRCC, even in patients with a favorable prognostic profile.