Purpose: Children with Ewing sarcoma (ES) routinely undergo surveillance imaging after completion of therapy; however, the medical benefit of this imaging remains unclear. We aimed to determine whether there is a difference in survival between patients whose relapse was detected based on development of new symptoms or by routine imaging. Methods: We retrospectively reviewed all patients consecutively diagnosed with ES at Children's Healthcare of Atlanta from 2000 to 2011. Patient characteristics and outcomes were compared based on whether their relapse was diagnosed based on symptoms or by routine surveillance imaging alone. Results: Thirty-three percent (28/85) of patients relapsed. Median age at time of relapse was 15.5 years (interquartile range: 12.5-18.0). Among the relapsed patients, 57% (16/28) were symptomatic and 43% (12/28) were asymptomatic, having relapse detected on surveillance imaging alone. The most common presenting symptom was bone pain occurring in 69% (11/16) of patients. The 5-year postrelapse overall survival for patients with symptomatic relapse was 0% (95% confidence interval [CI]: not estimated) compared with 15% (95% CI: 1-48) for patients with an asymptomatic relapse (p < 0.01). After adjusting for extent of disease and time to relapse, having a symptomatic relapse was still strongly associated with a worse outcome (hazard ratio: 9.68; 95% CI: 3.09-30.34). Conclusion: Patients with ES whose relapse is detected on imaging before the development of symptoms have significantly better outcomes, suggesting a potentially beneficial role of routine surveillance imaging in this population of patients. Further prospective analyses are needed to confirm these findings, and determine the optimal evidence-based imaging modality and schedule.
Keywords: Ewing; imaging; radiography; relapse; sarcoma; surveillance.