148P Diverse behavior of angiosarcoma: A call for a collaborative approach from a single center report

Methods: Patients diagnosed with U-LMS and NU-LMS between 2009 and 2015 were identified from Instituto Nacional de Enfermedades Neoplsicas (INEN) database.The primary tumor location and histological grade were assessed.Overall survival (OS) was estimated using the Kaplan-Meier method, and survival differences were analyzed using the log-rank test.Results: 144 patients were included in the study.The median age was 54 years (range: 5-82), 110 patients (76.4%) were female.39 patients (27.1%) were classified as U-LMS, and 105 (72.9%) as NU-LMS.NU-LMS subgroups included 31 patients (29.5%) with primary tumors in the extremities, 25 (23.8%) in the retroperitoneum, 14 (13.3%) in the abdominopelvic region, and 13 (12.3%)classified as visceral tumors; 20% of cases were not classified in these subgroups due to their heterogeneous location.The median OS for the entire cohort was 28 months (95% CI: 19.8-36.1).When analyzed by primary tumor location, the median OS for U-LMS was 24 months (95% CI: 12.1-35.8)vs. 39 months (95% CI: 22.6-55.4)for NU-LMS (p0.075).Among the NU-LMS subgroups, patients with extremity tumors had the best outcomes, with a median OS of 66 months (95% CI: 38.3-93.7)p0.001.Conclusions: LMS are rare and aggressive neoplasms, with limited data available in a Latin American center.Patients with NU-LMS demonstrated better OS compared to those with U-LMS.Further studies should be performed to explore treatment strategies, prognostic factors and the role of biomarkers.