CLRM-09 MAPPING THE DISTRIBUTION AND CLINICAL ASSOCIATIONS OF BRAIN METASTASES IN RENAL CELL CARCINOMA

Brain metastases (BrM) commonly occur in renal cell carcinoma (RCC) and often present with hemorrhagic features. The distribution patterns of BrM in RCC and their associations with clinical outcomes remain unclear. We conducted a retrospective neuroanatomical distribution analysis combined with clinical review of our surgical RCC BrM cohort. Sixty-seven BrMs from 46patients (age 63±10years, 25males) were included. The majority of BrM (55%) were found in the left hemisphere, with frontal (45%), parietal (21%), and occipital (18%) lobes being the most commonly affected areas. Hemosiderin deposits, as detected by MRI, were present in 82% of BrM, while hemorrhage, as detected by CT, was present in 80% of BrM. Patients with solitary BrM had a higher KPS (p=0.006) and lower disease burden (p=0.004) compared to those with multiple BrM. Mean 1D and 2D(RANO) tumor dimensions were 2.0±1.1cm and 4.7±4.9cm2, respectively, and correlated with the neutrophil count at BrM diagnosis (r=0.3; p=0.01). Hemosiderin deposits were associated with larger tumors (2.6±1.0cm vs. 1.8±0.7cm, p=0.04), lower platelet counts (p=0.01), and higher hemoglobin levels (p=0.08). Shorter Brain Metastasis-Free Survival was associated with hemosiderin deposits on MRI (log-rank p=0.04) and renal vein thrombosis (RVT) in the primary specimen (log-rank p=0.002). RVT at primary diagnosis was associated with both hemosiderin deposits on MRI (p=0.05) and hemorrhage on CT (p=0.03), and CNS progression-free survival was shorter in patients with RVT (7.3±1.7 months vs. 21.0±4.7 months). When including only significant predictors, right hemispheric BrM lateralization (HR 2.6, p=0.06), hemosiderin deposits in BrM (HR 6.5, p=0.02), and IMDC risk groups (intermediate HR=2.9; poor-risk HR=25.6; p<0.04) were independent prognostic factors for shorter OS on multivariable analysis. Our results demonstrate that mapping the BrM distribution o in RCC can provide clinically relevant insights. Hemosiderin deposits in BrM may have prognostic implications. Further analyses are ongoing.