SURG-13. GENOMIC ANALYSIS, SURGICAL TREATMENT AND OUTCOMES OF LOWER-GRADE GLIOMAS IN A SINGLE INSTITUTION

Abstract

AbstractOBJECTIVERecent research has demonstrated that IDH and 1p/19q status in lower grade gliomas better predicts clinical outcome than histological class. We reviewed our institutional outcomes based on these parameters combined with the extent of surgical resection and adjuvant treatment given. DESIGN: A 10-year retrospective case review. SUBJECTS: Patients undergoing biopsy or resection of lower-grade gliomas between 2005 and 2016 in our institution.RESULTS122 patients underwent biopsy or resection of a tumour on which genetic analysis was performed. 42 underwent a gross total resection (GTR), 72 received radiotherapy within 3 months of surgery and 28 received chemotherapy within 3 months of surgery. Those with IDH1 wildtype had a significantly increased risk of disease progression (coef 0.8019, p-value 0.0129) and of death (coef 1.21, p-value 0.0024), while those with 1p19q co-deletion and IDH1 mutation had a significantly reduced risk of disease progression (coef -2.4823, p-value 0.0157). Across all tumours, GTR significantly reduced the risk of disease progression (coef -0.8277, p-value 0.0073) and of death (coef -1.2029, p-value 0.0052) while radiotherapy significantly reduced the risk of death (coef -0.6789, p-value 0.0446) only.CONCLUSIONSOur outcomes based on genomic analysis are now more predictable than with the previous histological classification and are consistent with other published data. GTR and radiotherapy have been demonstrated to play a significant role in management. The ongoing review of treatment outcomes with respect to genomic classification will further inform the surgical and adjuvant management for all lower-grade glioma subtypes in the future.