In my understanding, pediatric ependymoma is still a surgical disease for which effective chemotherapeutic strategies have not yet been established (although there have been ongoing studies, e.g., reviewed in https://www.ncbi.nlm.nih.gov/pubmed/27866097 ). Pediatric ependymoma generally undergoes surgical resection, followed by conformal radiotherapy (and then second surgery depending on situations). So, the therapeutic efficacy depends on surgery.

I would hope that radiation oncologists could add more answers.