NCMP-06. THE RISK AND BURDEN OF THROMBOEMBOLIC AND HEMORRHAGIC EVENTS IN PATIENTS WITH MALIGNANT GLIOMA RECEIVING BEVACIZUMAB

Abstract

Abstract BACKGROUND Patients with high-grade gliomas (HGG) often receive anti-angiogenic therapy with bevacizumab to slow disease progression and/or palliate neurological symptoms. Bevacizumab has been associated with an increased risk of two major vascular complications: venous thromboembolism (VTE) and intracranial hemorrhage (ICH). We sought to identify clinical, pathologic, and radiographic variables correlated with risk of either event occurring in patients with HGG receiving bevacizumab. METHODS We retrospectively identified 94 patients with HGG who received bevacizumab at our center from 2015-2021. Variables included demographics, performance status, IDH, MGMT, vascular risk factors, baseline anti-coagulant/anti-platelet use, concurrent chemotherapy, and presence of macrobleeds on MRI (>1 cm3 susceptibility) at the time of bevacizumab initiation. We conducted competing risk analysis using subdistribution hazard models with death as competing risk for ICH or VTE. The effects of covariates on the incidence of hemorrhage or VTE were evaluated in univariate and multivariate settings. RESULTS Of 94 patients, 36 (38.3%) and 27 (28.7%) developed VTE and ICH, respectively. 31 (33%) did not develop either. ICH and VTE events occurred after a mean of 4.46 and 5.94 cycles of bevacizumab, respectively. 20 had baseline anti-platelet/anticoagulant use, and 16 had prior VTEs. Patients with macrobleeds on MRI had a larger HR of developing acute hemorrhage [HR=2.368 (1.112, 5.043), p=0.0254]. Patients older than 50 trended toward larger HR of developing VTE in univariate analysis that approached significance [HR=1.799 (0.889, 3.637), p=0.1023]. Sex, performance status, IDH, MGMT, vascular risk factors, baseline anticoagulant/anti-platelet use and concurrent chemotherapy were not significantly associated with occurrence of VTE. CONCLUSIONS The presence of macrobleeds on MRI is associated with increased risk of developing acute ICH while on bevacizumab. Older age at diagnosis of HGG may be associated with an increased risk of VTE in patients receiving bevacizumab. Larger studies are needed to confirm these findings.