Clinical Features and Outcomes of Infants With Ewing Sarcoma Under 12 Months of Age

Background. Ewing sarcoma peaks in incidence in adolescence. Infants <12 months old have rarely been reported. We aimed to compare clinical features, treatment, and survival of infants <12 months to those of older pediatric patients with Ewing sarcoma. Procedure. We utilized the SEER database to identify patients <12 months of age diagnosed with Ewing sarcoma between 1973 and 2011. We used Fisher exact tests to compare clinical features and treatment modalities between these patients and patients aged 1-19 years. Weused Kaplan-Meier methods to describe overall survival in these two groups. Results. Of 1,957 patients in the cohort, 39 (2.0%) were diagnosed at <12 months of age. Infants had a different distribution of primary tumor sites, with lower extremity tumors under represented. Compared to older patients, infants were more likely to have soft tissue tumors (81.6% vs. 27.1%; P<0.001); have primitive neuroectodermal tumor/Askin tumor (61.5% vs. 19.9%; P<0.001); and have tumors <8 cm (81.0% vs. 53.2%; P<0.014). Infants were less likely to receive radiation therapy (13.2% vs. 53.3%; P<0.001). Infants were at increased risk for early death (P<0.013 by Wilcoxon), though long-term overall survival was not different between age groups (P<0.25 by log rank). Conclusions. Ewing sarcoma is rare in infants, with different clinical presentations and treatment approaches. These patients appear to be at higher risk for early death, but long-term survival is similar to older pediatric patients. (C) 2015 Wiley Periodicals, Inc.