RARE-08. MULTI-INSTITUTIONAL ANALYSIS OF PEDIATRIC RELAPSED/REFRACTORY CENTRAL NERVOUS SYSTEM GERMINOMA

BACKGROUND: Relapsed central nervous system (CNS) germinomas are rare with no universal agreement regarding management. We explore prognostic factors that may impact the treatment of patients with relapsed CNS germinoma. METHODS: An international multi-institutional retrospective study of relapsed/progressive CNS germinomas was conducted. Data was summarized using descriptive statistics. Overall survival (OS) was evaluated using Kaplan-Meier and Fischer’s exact test to estimate odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Analysis included 21 patients (Male 71.4%) with relapsed/progressive germinomas from 7 sites. Median age at diagnosis was 15 years (interquartile range (IQR): 9.9-19) with 5% presenting with metastatic disease. Twelve patients (57.1%) achieved complete remission (CR) after initial therapy. Nineteen children (90.5%) suffered relapse. One (4.8%) suffered progression. The median time from diagnosis to relapse/progression was 21 months (range: 10-56 months) with 90.5% occurring within 24 months. 19 (90.5%) underwent chemotherapy, 9 (42.9%) bone marrow ablative therapy (HDCx), and 13 (61.9%) radiotherapy. At last follow-up, 88.9% of HDCx and 92.3% of radiotherapy recipients were alive. Of patients receiving radiation, 45% received whole ventricular irradiation, 25% craniospinal irradiation, and 5% focal irradiation (remainder unreported). Eleven children (52.4%) achieved CR after relapse/progression therapy and 16 (76.2%) were alive at last follow-up. Median time to last follow-up was 39 months (IQR: 18.43–89.50). Re-irradiation at relapse (OR=16, 95% CI: 1.27-200.9) and achieving complete response (CR) at relapse/progression (OR=4, 95% CI: 1.04-1.78) were associated with improved OS. CR after initial therapy (OR=0.857, 95%CI: 0.11-6.62) and HDCx at relapse/progression (OR=4, 95%CI: 0.36-44.13) were not associated with improved OS. CONCLUSIONS: Relapsed CNS germinomas are radiosensitive and salvageable by re-irradiation at relapse. This ongoing multi-institutional study will contribute to existing knowledge about relapsed/progressive CNS germinomas and inform prospective clinical trials to improve outcomes for children with relapsed/progressive disease.