2511 - Cumulative Incidence of Sarcoma Brain Metastases: Report from a High-Volume Cancer Center

A. Erjan¹, K. Jamora², E. Gutierrez², A. T. Santiago², B. A. Millar², N. J. Laperriere², T. D. Conrad², D. Keilty², P. Wong², P. Chung², C. N. Catton², D. G. Kirsch², and D. B. Shultz²; ¹Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, ON, Canada, ²Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada

Purpose/Objective(s): While carcinomas commonly metastasize to the brain, the incidence, and predictors of Brain metastases (BrM) in sarcoma patients remain poorly understood given their rarity. We aimed to determine the cumulative incidence (CI) and clinical factors associated with BrM in sarcoma patients. Materials/

Methods: We retrospectively analyzed data from all sarcoma patients who presented to our center between 2006 and 2023. The CI function was used to analyze time to BrM, with incidence stratified by key variables. Univariable (UVA) and multivariable analyses (MVA) were conducted to evaluate factors associated with BrM incidence.
Results: Among 3,766 sarcoma patients, 101 developed BrM. CI rates were 2.2%, 2.9%, and 3.3% at 24, 48, and 72 months, respectively, with a median time to BrM of 17 months. On UVA, intrathoracic and uterine primary locations, ASPS, Epithelioid, Intimal histologic subtypes, and metastatic stage at diagnosis were associated with increased CI of BrM. In contrast, age = 59, primary retroperitoneal location and liposarcoma subtype were associated with a decreased CI. On MVA the following predictors remained significant: intrathoracic and uterine primaries (HR 18.0, 95% CI 8.52–38.0, P<0.001; HR 6.72, 95% CI 2.56-17.6, P<0.001), ASPS and Epithelioid Sarcoma (HR 4.89, 95% CI 2.17–11.0, P<0.001; HR 2.77, 95% CI 1.02–7.54, P=0.047), age = 59 years (HR 0.45, 95% CI 0.27–0.73, P=0.001) and liposarcoma (HR 0.12, 95% CI 0.03–0.60, P=0.009).
Conclusion: This report provides valuable insights into the CI of BrM among sarcoma patients, highlighting the impact of age, tumor location, and histologic subtype on BrM incidence. These findings underscore the importance of tailored surveillance for high-risk patients, potentially leading to improved outcomes.