EPCO-21. IDENTIFYING FACTORS THAT PREDICT GENETIC PREDISPOSITION TO BRAIN TUMOR FORMATION

Abstract

Abstract INTRODUCTION Increasing evidence suggests that glioma formation may have a greater hereditary component than initially thought. Identification of individuals with a genetic predisposition is critical for appropriate monitoring and treatment. OBJECTIVE To analyze the personal and family histories of patients with intrinsic brain tumors seen in a cancer genetics clinic to inform referral practices. METHODS A prospective database of cancer genetics data from a large multidisciplinary cancer genetics clinic was queried for brain tumors from 2007-2023. Genetic test results, age of brain cancer diagnosis, number/types of distinct cancers, oncologic family history, and personal and family history of cancer syndromes were recorded. Fisher’s exact tests and ANOVA were used for analysis. RESULTS Sixty-five patients with intrinsic brain tumors, which included 53 high and low grade gliomas, were identified. There were 33 males; the mean age of diagnosis was 34.6±23.4. Fifty-three (81.5%) had genetic testing performed. Of these, 19 (35.8%) were found to have germline pathogenic variants (PV), 10 (18.9%) had variants of unknown significance (VUS), and 24 (45.3%) were found to have no mutations. Patients with PVs were younger than patients with normal genetic screening (28.1 vs 41.5 years, p= 0.06), and patients with either PV or VUS were significantly younger (p= 0.04) than patients with normal screening. Regarding personal cancer history, patients with and without PVs had a similar history of personal cancers (p= 0.20). Regarding family history, only 1 patient with PV had a family history of brain cancer compared to 15 in patients with negative testing (5.3% vs 44.1%, p= 0.004). CONCLUSIONS Only younger age at presentation was identified as a predictor of a PV or VUS. A lack of personal/family history of cancer does not preclude a genetic predisposition to cancer. We recommend that younger patients with intrinsic brain tumors should be referred for genetic testing.