P04.02.A Integrated diagnosis and therapeutic decision of pediatric nervous system tumors using a comprehensive genomic profiling test

Abstract Background Nervous system tumors (NST) are one of the leading causes of cancer-related death in children. Next-generation sequencing has enabled the identification of an increasing number of genetic markers, allowing for a more accurate diagnosis, and may help guide clinicians towards a more specific therapeutic approach. Material and Methods Retrospective cohort study of pediatric and young adult patients with NST analyzed with FoundationOneHeme® (FOH) panel from March 2020 to April 2021. This panel was requested, in addition to previously performed pathological reviews and routine genetic tests, in order to obtain more accurate diagnoses and/or possible therapeutic targets. Results Fifty NST were analyzed with FOH panel, corresponding to 49 patients. Median age at NST diagnosis was 13 years (range 0-23 years); 50% were females. Initial diagnoses were: 10 pilocytic astrocytomas, 10 diffuse gliomas, 5 ependymomas, 6 mixed neuronal-glial tumors, 7 embryonal tumors, 3 meningeal tumors, 5 peripheral nervous system tumors (PNST) and 4 other types of tumors. There was a change in the final integrated diagnosis after performing the FOH panel in 10 patients (1 pilocytic astrocytoma, 3 diffuse gliomas, 4 mixed neuronal-glial tumors and 1 PNST). In thirty patients, at least one possible therapeutic target was identified: in 5 patients the target therapies are approved for the patients’ tumor type; in 20 patients, target therapies are approved for the same mutations in other tumor types; and in 30 patients target therapies are still being evaluated in ongoing clinical trials. After the results of the FOH panel were known, the previous therapeutic approach was changed in 15 patients, but in only 4 this was attributed to the new genomic findings. Conclusion Comprehensive genomic profiling tests can improve diagnostic accuracy and allow for a more reliable approach to the management of pediatric patients with nervous system tumors. Although in most patients there was no immediate therapeutic application of the potential targets found, the genomic data obtained could be very useful to patients who may have tumor progressions in the future.