Incidence and Outcomes of Extremity Soft-Tissue Sarcomas in Children

We studied the outcomes of pediatric extremity tumors on a population scale.The Surveillance, Epidemiology, and End Results database (1973-2006) was queried for all patients under 20 y of age.Overall, 1175 patients were identified. The median age at diagnosis was 12 y, but most patients were ≥10 y of age (72%, n = 842). Most tumors were non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) (79%, n = 879). The most common tissue of origin was muscle (43%, n = 474). Most rhabdomyosarcoma (RMS) (n = 220) were alveolar type (n = 140). Most patients presented with local disease (64%, n = 699), and underwent surgical intervention (88%, n = 1027), but did not have radiotherapy (62%, n = 710). RMS was more likely to present in younger children (P < 0.001) and with distant disease (P < 0.001). Older patients were more likely to receive radiotherapy than infants (P < 0.001). Overall 5-y survival was 79%. RMS had significantly worse 5-y survival (56% versus 85% for NRSTS, P < 0.001). Surgical intervention was associated with higher 5-y survival (84% versus 48%, P < 0.001). Radiotherapy was associated with worse 5-y survival (74% versus 83%, P = 0.002). Multivariate analysis identified RMS (HR 2.20, P < 0.001), nerve and muscle (not synovial sarcoma) tissue of origin (HR 2.26, P = 0.002, and HR 1.59, P = 0.036), regional or distant disease (HR 1.65, P = 0.011, and HR 5.96, P < 0.001, respectively), and lack of surgical intervention (HR 2.20, P < 0.001) as independent predictors of poor outcome.Extremity sarcomas are most common in older children. RMS is more common in younger children, but is associated with lower survival, and is an independent prognostic indicator of mortality.