1968P - Metastatic Ewing sarcoma, patterns of care and outcomes of patients in a real-life setting: The Metabone national observational study

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 1^rst line, 5.5 months [95%CI 3.8; 6.8] for 2^nd line and 5.5 months [95%CI 3.7; 7.7] and 3.6 months [95%CI 2.5; 4.4] for 3^rd and 4^rth lines. 66 (44.9%) pts were included in a CT at least once in the metastatic setting, 35 in 1^rst line, 28 in 2^nd line and 15 and 22 in 3^rd and 4^rth 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.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Institut Bergonie.

Funding

This study received a funding from Bayer and a grant from INCA.

Disclosure

All authors have declared no conflicts of interest.