Abstract 124P
Background
Ewing's Sarcoma (ES) is a rare and aggressive malignancy that predominantly affects children and adolescents, with less favorable outcomes in adults. We aim to determine disparities in treatment approaches and outcomes across age groups.
Methods
A retrospective study was conducted at the Salah Azaiz Institute including all patients diagnosed and treated for Ewing’s Sarcoma between 2001 and 2023.We collected data relating to delay of treatment initiation, dose reductions, pathological response and survival.
Results
We included 76 patients (55 males, 21 females). The median age of diagnosis was 15 years (±8.74). The lower limb was the predominant location (44%) followed by pelvis (21.3%) and ribcage (16%). Extra skeletal tumors represented 5.3%. Metastases were present at diagnosis in 17.3% of patients, and were significantly more frequent in adolescents and YA (AYA) (22%) compared to children (4.7%) (p=0.036). AYA had a significantly longer treatment initiation delay (median of 8.5 weeks compared 3.6 weeks in children, p=0.004). Chemotherapy regimens included VDC/IE in 33.3% and VIDE in 66.7% of cases. Relative-Dose-intensity (RDI) reached ≥70% in 66.7% of children, 33.3% of adolescents, and none of the adults (p=0.02). However, dose reduction was more frequent in children (64%) than in adults (30%) (p=0.026), aiming to maintain a higher RDI in children. Surgical resection was performed in 86.7% of cases. Pathological response was good in 49.2% and poor in 50.8%. Good responders represented 62% of operated children and 42.8% of operated AYA. Overall survival (OS) was significantly improved in children. Five-year OS was 44.6%, with a higher risk of mortality in AYA (HR 4.08, 95% CI 1.23–13.52). The median OS of 148 months in children versus 28 months in AYA (p=0.012). Relapse occurred in 39.5% of cases, with 16 local and 15 metastatic (primarily pulmonary) recurrences. Median progression-free survival (PFS) was 23 months, with a 3-year PFS of 49.3%. PFS was significantly poorer in AYA (11 months) compared to children (74 months) (p=0.001).
Conclusions
Outside the pediatric population, patients continue to face challenges such as poor representation in large phase III trials, delayed treatment and reduced dose intensity.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.