Background Metastatic Ewing Sarcoma (MES) has a poor prognosis, and therapeutic options are scarce in this rare disease. Large observational studies are needed to improve patients (pts) care and help designing future clinical trials. Methods Treatment characteristics, outcomes, and prognostic factors of pts > 12 year-old treated for a MES in 10 French national reference network centers from 2008 to 2018 and included in the prospective database of the French Sarcoma Group were analyzed. The primary objective was to describe treatment modalities of pts with MES in a real-life setting, including systemic treatment (ST) regimen, access to clinical trials (CT) and loco-regional (LR) procedures. Secondary objectives were to assess pts outcome in terms of time to next treatment (TNT), progression free survival (PFS) and overall survival (OS) for each line of ST, as well as the impact of CT access and LR procedures on TNT, PFS and OS in the metastatic setting. Results 156 pts with MES were included, 80 pts were metastatic from diagnosis, 76 pts had a metastatic relapse. Median follow-up was 76.8 months [66.7; 88.5]. Median age was 21 years (12-86), 44 (28.2%) pts were < 18 year old at metastasis diagnosis. Main primary location was pelvic (34.6%). 147 (94%) pts received ST in the metastatic setting, with a median of 3 lines (IQR 2-5). 102 (65.4%) pts received more than 2 lines. 95 (60.9%) of pts underwent LR procedure for metastasis, including radiation therapy (84.2%), radiological procedures (12.6%) or surgery (8.4%). 30 (31.6%) pts had multiple procedures. Median OS from metastasis diagnosis was 26.6 months [95%CI 21.0; 32.2]. Median TNT was 5.3 months [95%CI 4.9; 5.6] for 1rst line, 5.5 months [95%CI 3.8; 6.8] for 2nd line and 5.5 months [95%CI 3.7; 7.7] and 3.6 months [95%CI 2.5; 4.4] for 3rd and 4rth lines. 66 (44.9%) pts were included in a CT at least once in the metastatic setting, 35 in 1rst line, 28 in 2nd line and 15 and 22 in 3rd and 4rth lines. Conclusions This large multicentric observational study details real-world data on patterns of treatments for pts with MES in France. Detailed ST regimens used, median TNT, PFS and OS according to line and ST regimen as well as factors associated with TNT, PFS and OS will be presented at the meeting.< Réduire