EPEN-03. THE MANAGEMENT OF PEDIATRIC AND ADOLESCENT SPINAL EPENDYMOMA; A 20-YEAR NATIONAL EVALUATION INVOLVING UNITED KINGDOM PEDIATRIC ONCOLOGY PRIMARY TREATMENT CENTERS ON BEHALF OF THE UK CHILDREN’S CANCER AND LEUKAEMIA GROUP (CCLG)

Abstract

Abstract INTRODUCTION Pediatric spinal ependymomas account for approximately 1% of childhood CNS tumors. Most are myxopapillary ependymomas (MPEs). For symptomatic cases, maximal safe surgical resection is the accepted therapeutic standard. However, a role for adjuvant therapy is unclear, underpinned by low incidence rates, inadequate trial data and recent WHO upgrading of the MPE variant. This retrospective national service evaluation aimed to provide safety and outcome data, from which future management guidance could be developed. METHOD Children, teenagers and young adults diagnosed with a spinal ependymoma of any WHO grade since 2000 across 17 UK CCLG centres were evaluated. Patient demographics, therapies, adverse events, and outcomes were captured. RESULTS 102 patients were evaluated. Ten children had NF2 (median age 11 (7.6 – 14) years) with nine located in the cervicomedullary region. All ten patients were alive following surveillance (n=3) or surgical intervention (n=7) with an estimated median PFS of 5.4 (1.7 – 9.1) years. For the remaining 92 patients (median age 12 (0.7 – 19) years), 63% of tumors were lumbosacral, 73% demonstrated MPE morphology and 16% were metastatic. The median symptom interval was 4 (0 - 36) months. Progression or relapse was reported in 30/92 (33%), with a 5-year PFS of 62(+ 6)%, yet only 4 disease-related deaths occurred (mean follow-up 6.8 years; no MPEs). Across this non-NF2 cohort, gross/near total resection and upfront adjuvant radiotherapy independently reduced disease progression risk (p < 0.05). However, improved local control from early irradiation was not statistically proven when localized disease or MPEs were exclusively scrutinized. No radiotherapy-related high-grade toxicity was reported. DISCUSSION Pediatric spinal ependymomas are rare tumors demonstrating excellent survival, particularly MPEs. Maximal safe surgery and early adjuvant radiotherapy can improve local control rates, but European collaboration will be required to evaluate efficacy for certain tumor and clinical subgroups. Conclusions could support future national management guidelines.