EPEN-13. OUTCOMES AFTER FIRST RELAPSE OF CHILDHOOD INTRACRANIAL EPENDYMOMA: A SINGLE INSTITUTION EXPERIENCE

Abstract INTRODUCTION: Ependymoma is the third commonest malignant CNS tumor in children. Despite multimodal therapy, prognosis of relapsed ependymoma remains poor with long-term progression-free survival (PFS) of approximately 30%. Approaches to treating relapsed ependymoma are extremely varied. Here, we describe our experience and clinical outcomes of children after first relapse of intracranial ependymoma. METHODS: We performed a retrospective, IRB approved, chart review of patients with recurrent intracranial ependymoma treated at Dana-Farber / Boston Children’s Cancer and Blood Disorder Center from 1990 to 2017. RESULTS: Thirty-four patients with relapsed intracranial ependymoma (12 ST, 21 PF, 1 metastatic) were identified. Median time-to-first-relapse was 13.7 months (range:2.0–53.8). Eight patients had metastatic disease at first relapse. Five-year PFS and overall survival (OS) after first relapse was 23.5% and 60.9%, respectively. Median PFS and OS were 12 months and 66 months. Treatments for first relapse included surgery, radiation and/or chemotherapy/biologic therapy. GTR and localized disease were associated with improved OS on univariate analysis, with GTR being an independent prognostic factor for PFS and OS on multivariate analysis (p=0.02 & 0.013, respectively). Median PFS and OS for patients with GTR was 1.5 and 13 years, respectively (versus 0.4 and 2.3 years for STR / no resection [p=0.023 & 0.001, respectively]). Eighteen patients received radiation at first relapse (14 focal radiation, 8 re-irradiation). Patients who were radiated/re-irradiated at relapse showed longer median PFS and OS, however, these did not meet statistical significance. Chemotherapeutic (n=16) and biologic agents (n=3) used in this cohort were heterogenous and did not significantly impact outcome. Median time-to-second-relapse was 10.2 months (range:2.0–124.8). CONCLUSION: Relapsed intracranial ependymoma has a poor prognosis and unrelenting chronic course despite multimodal therapy. GTR is associated with improved outcomes after first relapse and should be pursued when possible. Novel therapeutic strategies are needed for this disease.