TBIO-12. Screening for Cancer Predisposition Syndromes in Pediatric Neuro-Oncology Patients: a Single Institution Experience

BACKGROUND: Traditional screening for cancer predisposition syndromes centers on family history, phenotypic features, and tumor histology. With expanded accessibility of next generation sequencing, identification of de novo germline mutations is increasing and the predictive value of family history has become less clear. While identification of germline mutations often affects care of pediatric neuro-oncology patients, germline sequencing is not currently standard of care. We hypothesize that routine screening for germline mutations in pediatric neuro-oncology patients reveals unsuspected cancer predisposition syndromes and impacts care. METHODS: A retrospective analysis was performed on pediatric neuro-oncology patients at a single institution who had targeted next generation sequencing of approximately 500-cancer associated genes (UCSF500) on tumor and paired germline DNA. We determined the proportion of patients with germline mutations and assessed impact on future screening and current tumor treatment. We interrogated clinical notes, family history, and interviewed treating physicians to determine if predispositions were previously suspected. RESULTS: Between June 2015-December 2019, 187 patients had paired testing; of these 29 (16%) harbored germlines mutations that were pathogenic or likely pathogenic. Germline mutations were found in patients with high-grade glioma (n=12), low-grade glioma (n=7), medulloblastoma (n=4), ATRT (n=2), and choroid plexus papilloma (n=1). Known cancer predisposition syndromes were identified or confirmed in 18 patients. Of these, the most common alterations were in TP53 (n=6), CHEK2 (2), NF1 (n=2), SMARCB1 (n=2), and PTEN (n=2). Patients were referred to genetic counseling in 26 cases and malignancy screenings were implemented in 25 cases. Germline findings affected malignancy treatment in 10 cases, most often through use of targeted therapeutics or avoidance of radiation. CONCLUSIONS: In our series, we found that 16% of pediatric neuro-oncology patients harbored germline mutations, the majority of which were associated with cancer predisposition syndromes. These results support standardizing screening for pathogenic germline mutations in pediatric neuro-oncology patients.