Conventionally Fractionated Re-irradiation for Recurrent Ependymoma.

BACKGROUND: Reirradiation is used for children and adolescents with recurrent ependymoma after prior surgery and focal irradiation. This study assessed the long-term benefits and risks of a second course of fractionated radiotherapy, patient selection, factors associated with progression-free survival (PFS) and overall survival (OS), and the role of craniospinal irradiation (CSI) at first recurrence. METHODS: From July 1994 to January 2024, 150 pediatric ependymoma patients at St. Jude Children's Research Hospital received a second course of fractionated radiotherapy. Sixty-four were enrolled in a prospective trial. Inclusion required conventional fractionation (≥50.4Gy) for both courses, with CSI for metastatic disease. Kaplan-Meier estimates measured PFS and OS, Cox models assessed associations with covariates, and competing risks analysis evaluated necrosis and death from complications. RESULTS: At 10 and 20 years, PFS/OS for the cohort were 19.5%/34.3% and 9.0%/13.1%, respectively. Females had significantly better outcomes, and survival varied by initial failure pattern. No significant difference in PFS (p = 0.1351) or OS (p = 0.2705) was found between focal irradiation and CSI for patients with local failure. Necrosis was higher with proton therapy versus photons; grade 3 necrosis after reirradiation occurred in 19.9%. The 10-year cumulative incidence of death from complications or secondary tumors was 8.5%. CONCLUSIONS: A second course of conventionally fractionated radiotherapy can extend survival in recurrent pediatric ependymoma, but prognosis remains poor, especially for those with combined local and distant failure or adverse features. CSI did not improve outcomes for local failures. Proton therapy increased necrosis risk, emphasizing the need for careful selection and follow-up.