RARE-07. BONE MARROW ABLATIVE CHEMOTHERAPY ASSOCIATED WITH IMPROVED OUTCOMES AMONG PATIENTS WITH RELAPSED CENTRAL NERVOUS SYSTEM NON-GERMINOMATOUS GERM CELL TUMORS

PURPOSE: Patients with relapsed/refractory central nervous system (CNS) non-germinomatous germ cell tumors (NGGCTs) have poor outcomes. There is no universal agreement on managing these patients secondary to the rarity of the disease and lack of prospective trials. We aim to explore prognostic factors that may help guide the management of patients with relapsed/refractory CNS NGGCTs. METHODS: We performed a multinational retrospective study of relapsed/refractory CNS NGGCTs. We summarized all data using standard descriptive statistics. Overall survival (OS) was evaluated using Kaplan-Meier and Fisher’s exact test to estimate odds ratios (OR) and 95% confidence intervals (CI) using SPSS software. RESULTS: We identified 28 patients from 7 centers. Twenty-three patients (82%) were males. The median age at initial diagnosis was 11 years (range: 8-15). Twelve patients (43%) suffered from relapse, and 16 patients (57%) had an initial refractory disease. The median time to first relapse/progression was 29 months (range: 5-26). Eight patients (29%) received bone marrow ablative chemotherapy (HDCx) at relapse/progression. Sixteen patients (57%) received re-irradiation at relapse/progression. Six patients (21%) achieved complete remission (CR) at relapse. Only eight patients (29%) were alive at the last follow-up. The median follow-up time since relapse/progression was 16 months (range: 1 -153 months). HDCx (OR=25, 95%CI: 2.9-2223) – not re-irradiation (OR=7.8 95%CI: 0.795-76.1) – was associated with being alive at the last follow-up. All patients who achieved CR at the end of relapse treatment survived. Only one patient with the refractory disease was alive at the last follow-up. CONCLUSIONS: Patients with refractory CNS NGGCTs have dismal outcomes. HDCx and achieving CR at the end of relapse therapy are associated with improved survival. A multinational registry is needed to collate standardized data to inform future prospective clinical trials and improve the outcomes of patients with relapsed/refractory CNS NGCCTs.