399PD - Association of systemic inflammation with local tumour characteristics and survival in glioma patients

Immunotherapy has yield only modest clinical efficacy in glioma so far. However, gliomas are characterized by a range of immune suppressive features. Here, we aimed to analyze the correlation of systemic inflammation with local tumor characteristics and overall survival in glioma patients. Glioma patients were recruited at time of diagnosis or recurrence within the Vienna Cancer and Thrombosis Study (CATS). At study inclusion, a blood draw was performed. IDH1 mutation, PD-L1 and podoplanin in glioma were assessed via immunohistochemistry. 193 glioma patients (4.7% diffuse glioma, 19.7% anaplastic glioma, 75.6% glioblastoma) were included. IDH1 mutation was present in 40/193 (20.7%) patients, PD-L1 expression was observed in 20/193 (10.4%) patients, and podoplanin positivity was found in 134/193 (69.4%) patients. IDH1 mutation was associated with higher platelet count (median: 303 vs. 232G/L, p=0.001) and lower neutrophil count (4.71 vs 6.55G/L, p=0.021) as well as lower neutrophil/lymphocyte (N/L) ratio (3.34 vs. 5.13, p=0.016). PD-L1 was associated with higher monocyte count (0.657 vs. 0.450G/L, p=0.008), higher C-reactive protein (CRP) (0.43 vs. 0.1mg/dL, p=0.005) and higher fibrinogen (379 vs. 303mg/dL, p=0.001). Podoplanin was associated with higher leukocyte count (8.88 vs 7.22G/L, p=0.040), higher neutrophil count (6.44 vs 5.03G/L, p=0.048), higher N/L ratio (5.4 vs. 3.2, p=0.006) and lower platelet count (227 vs 289G/L, p