Reirradiation for Patients With Recurrent Ependymoma Across the Age Spectrum.

Purpose: In patients with locally recurrent ependymoma, previous data have shown that repeat radiation therapy (RT2) with craniospinal irradiation (CSI) improves disease control compared with focal RT2 alone. This study aimed to report long-term outcomes of adults and children with recurrent intracranial ependymoma, including those treated with CSI. Methods and Materials: In this retrospective, single-institution study, we identified 48 patients treated with RT2 for recurrent ependymoma between 1999 and 2024. The primary endpoint was overall survival (OS) with the start of RT2 as the index time. CSI was prescribed to 23.4 or 36 Gy, followed by focal boost radiation therapy to 54 Gy. OS was estimated using the Kaplan-Meier method; groups were compared using the log-rank test. Results: The median age at initial diagnosis was 6.5 years (range, 0.8-62.3 years), and the majority of patients were pediatric (83%; aged <18 years) with a posterior fossa (PF) tumor location (67%). Of the 35 patients with available molecular pathology, 23 had PF-A, and 11 had a zinc finger translocation associated fusion. The median follow-up was 9.1 years. Gross total resection of all disease prior to RT2 was associated with better 5-year OS (57% vs 19%; Conclusions: In this single-institution cohort of patients with recurrent ependymoma and long-term follow-up, gross total resection of recurrence was associated with better survival, and locally recurrent patients treated with CSI-RT2 had longer OS. Further work is required to determine the independent effects of CSI-RT2 together with the extent of re-resection.