Recurrence of Ewing sarcoma: Is detection by imaging follow-up protocol associated with survival advantage?

Background: The Cooperative Ewing Sarcoma Study and the Late Effects Surveillance System of the Society for Paediatric Oncology and Haematology recommend a structured follow-up imaging protocol (FUIP) for patients with Ewing sarcoma (EwS) with decreasing frequency of imaging over the first 5 years. The present study aims to assess the effectiveness of the FUIP for EwS patients regarding survival after relapse. Patients and methods: A retrospective multicenter analysis on 160 eligible patients with EwS recurrence was performed. Potential survival differences following recurrence diagnosis between patients with protocol-detected and symptomatic relapse were investigated using the Kaplan–Meier method. Additional subgroup analyses were performed on the relapse type. Overall survival (OS) was calculated from diagnosis of relapse to last follow-up or death. Results: In the multicenter analysis, recurrence was detected by FUIP in 77 of 160 patients (48%) and due to symptoms in 83 patients (52%). Regarding the entire study population, OS was significantly superior in patients with protocol-detected relapse compared to patients with symptomatic relapse (median, 2.4 vs. 1.2 years; P < 0.001). In the subgroup analyses, patients whose lung recurrences were detected by the FUIP experienced longer survival after recurrence than those whose recurrences were detected symptomatically (P = 0.023). In the 83 symptomatic patients, pain was the most prevalent symptom of relapse (72%). Conclusion: FUIP may benefit survival in EwS relapse, especially in lung recurrence. Pain was the leading symptom of relapse.