GCT-20. Multi-Institutional Analysis of Pediatric Relapsed/Refractory Central Nervous System Germ Cell Tumors

Central nervous system (CNS) germ cell tumors (GCTs) constitute ~ 4% of primary pediatric brain tumors in the United States. While multimodality therapy approaches have ensured >80% survival benefit, these patients still experience relapses, with no established standard of care. Their rarity limits knowledge of their outcomes and associations with location, metastatic status, impact of surgery, serum, and cerebrospinal fluid (CSF) biomarkers, to only a few smaller trials and case series.This international multi-institutional retrospective study for relapsed/refractory germinomas and NGGCTs, will evaluate the association between different treatment modalities and 5-year OS and EFS; patterns of relapse, including along biopsy tracts; and potentially identify predictors of recurrence. De-identified patient data at primary and relapse time points will be collected focusing on treatment approaches such as surgery, conventional/high dose chemotherapy, photon/proton radiation therapy; timing and site of relapse; imaging characteristics and serum/CSF biomarkers (BHCG/AFP). Our collaborators include multiple sites across North America, Australia, Europe, Africa, South America, the Middle east, India, Singapore, and Malaysia. 6 recurrent intracranial germinomas on the CBTN (Children’s Brain Tumor Consortium) database were assessed, demonstrating a male gender preponderance (4) and recurring in the suprasellar region (3), frontal lobe (2) and spinal cord (1). 2 underwent gross total resection while 1 had biopsy only. Conventional or high-dose chemotherapy was administered in 5, while 2 received craniospinal and 1 proton radiation. 4 patients are alive. Median OS was 738 days and EFS 1093 days. However, biomarker (AFP/BHCG) data was unavailable. Updated results will be presented at the conference. With global partnership and contribution, we anticipate this study to help bridge existing gaps in our knowledge of this rare patient cohort and establish a consensus standard of care, through prospective clinical trials in the future. We acknowledge the CBTN for kindly providing data access.