Mortality in young adults with Ewing sarcoma treated at specialized cancer centers in California.

Abstract

10538 Background: Ewing sarcoma is a rare malignancy of the soft tissue or bone that is most frequently seen in children and adolescents. One study suggested that care at specialized cancer centers (SCC) may mitigate survival disparities associated with public insurance in patients with sarcoma, but no large population-based studies have considered how location of care affects survival outcomes. Methods: We performed a retrospective, population-based cohort analysis of patients hospitalized within one year of diagnosis with primary Ewing sarcoma between 2000–2013 using the California Cancer Registry linked with state hospitalization data. Patients were divided into two groups based on whether they received inpatient treatment at a SCC [Children’s Oncology Group (if age ≤25) and/or National Cancer Institute-designated center] or not. We excluded 12 patients whose location of cancer treatment could not be determined. Multivariable Cox proportional hazards regression identified factors associated with mortality. Results are presented as adjusted hazard ratios (HR) and 95% confidence intervals (CI). Results: Of the 470 patients with newly diagnosed Ewing sarcoma, 40% were female, 52% were non-Hispanic white, and 53% had private health insurance. Sixty-one percent received their inpatient care at a SCC. Multivariable analysis across all ages demonstrated that higher mortality was associated with increasing age, metastatic disease, and large tumors, but mortality was not impacted by treatment at an SCC (HR 0.77, CI: 0.55-1.08; p = 0.134). However, when analyses were stratified by age, treatment at a SCC was associated with lower mortality among patients ages 19–39 years, but not among younger or older patients, and this association was only apparent within 2 years of diagnosis (HR = 0.43, CI: 0.23-0.79; p = 0.007). Conclusions: Our results suggest that treatment for Ewing sarcoma at a SCC significantly improves survival in young adults adjusted for other factors known to be associated with poor prognosis (metastatic disease, larger tumor size and older age). The lower mortality in this age group may be due to access to clinical trials and other specialized services specific to young adults available at SCCs.