KEY POINTS
- The retrospective cohort included 41 patients with recurrent pediatric ependymoma who received proton therapy as their second radiation course. Across subsequent recurrences, these patients ultimately underwent 126 radiation courses, including 100 proton courses.
- Median age at initial diagnosis was 3.3 years and at reirradiation 8.5 years. Most tumors were infratentorial (73%) and historically classified as anaplastic (83%); local recurrence was the first failure pattern in 71%.
- Reirradiation was focal in all patients at first recurrence, with a median dose of 52.2 GyRBE. Median follow-up after the second RT course was 6.9 years, providing unusually mature data for this rare setting.
- Five-year outcomes after reirradiation were 49.9% local control, 32.5% progression-free survival and 64.0% overall survival. One-year and three-year overall survival remained high at approximately 97% and 75%, respectively.
- Failure remained predominantly local. Among patients whose first recurrence was local, 5-year local control was 41.0%; nevertheless, more than half of those with an initial local failure were disease-free at last follow-up, often after additional salvage therapy.
- Long-term toxicity was relatively limited considering repeated irradiation. 58% had no documented long-term radiation toxicity, while most recorded events were grade 1-2, including hearing loss, endocrine effects, visual changes and radiographic or symptomatic radiation injury.
- One child developed grade 3 radiation injury 17 months after reirradiation, requiring hospitalization and treatment with steroids, bevacizumab and hyperbaric oxygen; residual weakness remained. No grade ≥4 toxicity was reported. One patient developed an in-field meningioma after two local radiation courses.
- Interpretation is limited by retrospective selection, a small rare-disease cohort and missing modern molecular classifications such as 1q status, posterior fossa A/B group and ZFTA fusion in many historically treated patients.
CLINICAL TAKEAWAY
Proton reirradiation can provide meaningful long-term survival for selected children with recurrent ependymoma, with severe late toxicity uncommon in this series despite substantial prior treatment. These data strengthen the rationale for considering focal proton reirradiation as part of salvage therapy, ideally alongside maximal safe resection, while the optimal role of focal treatment versus craniospinal irradiation remains unresolved.