(P 294) COMPARING HIGH-GRADE NON-RHABDOMYOSARCOMA SOFT TISSUE SARCOMA IN ADULT AND PEDIATRIC POPULATIONS

Objective: Soft tissue sarcoma (STS) is rare in pediatric patients with treatment and outcomes data lacking compared to adults. The purpose of this study is to compare our institution’s treatment and oncologic outcomes of high-grade STS in adults and children.

Methods: Four-hundred-and-fourteen (383 adult:31 pediatric) patients with high-grade non-rhabdomyosarcoma extremity STS were reviewed. Mean age at diagnosis was 63±15 and 11±5 years in adults and children, respectively. Mean follow-up was 5±4 years.

Results: Mean tumor size was similar in adults and children (9±6 vs. 8±7 cm, p=0.6) as were rates of metastatic disease on presentation (6% vs. 6%, p=0.9). Pre-operative radiation therapy was employed more frequently in adults (83% vs. 45%, p< 0.0001), and post-operative chemotherapy was utilized more in children (48% vs. 84%, p=0.0001). Use of pre-operative chemotherapy (33% vs. 39%, p=0.5) and post-operative radiation (10% vs. 13%, p=0.6) were similar in adults and children. Limb salvage was performed in 71% of adults and 84% of children (p=0.1). Five-year local recurrence free survival (LRFS, 86% vs. 85%, p=0.7, Figure 1) and metastatic disease-free survival (MDFS, 69% vs. 83%, p=0.08, Figure 2) were similar between adult and pediatric patients. Overall survival (OS) was higher in the pediatric cohort compared to adults (p=0.006) with 5-year OS of 67% and 80% (Figure 3).

Conclusion: Treatment of high-grade STS was treated differently in pediatric and adult patients with pre-operative radiation more utilized in adults and post-operative chemotherapy more utilized in children. LRFS and MDFS, however, were similar between groups with greater OS of the pediatric cohort.