P17.55UNRAVELLING GRADE 3 GLIOMAS

INTRODUCTION: Patients diagnosed with WHO Grade III Gliomas experience huge variations in overall survival and treatment response. In general, Grade II and Grade IV gliomas behave more predictably. We have attempted to identify factors within grade III gliomas that may better inform clinicians about the prognosis of this heterogeneous group of tumours. METHODS: Retrospective (1988-2013) case note, database, cytogenetic and tissue sample review of patients histologically diagnosed with WHO Grade III Gliomas. Demographics, molecular data (1p19q co-deletion, IDH mutation, Ki67/MIB), percentage of Grade II features and overall survival (OS) was analysed. Mortality was defined as any cause of death within 12, 18, 24, 36, 48 and 60 months of diagnosis. Results were statistically analysed by Kaplan-Meier and Log Rank (Cox Proportional Regression Hazard) Testing (p 48 months) was better for females. Tissue analysis for percentage Grade II features is ongoing. CONCLUSION: Debulking surgery, adjuvant therapy and age are well-established prognostic indicators. Molecular factors are possibly more weighted factors in predicting tumour behaviour and outcome. Routine availability of molecular genetics and the percentage of Grade II features will likely redefine this group of tumours into subcategories.