Risk of Adverse Vascular Events in Newly Diagnosed Glioblastoma Multiforme Patients Treated with Bevacizumab: a Systematic Review and Meta-Analysis

Previous evidence suggests that the humanized anti-VEGF antibody bevacizumab increases thrombosis risk in glioma patients. Here, we comprehensively assessed the risk of adverse vascular events in adult glioma patients receiving bevacizumab therapy. Systematic searches of MEDLINE, EMBASE, and the Cochrane Library were conducted to find prospective phase II/III clinical trials on adult bevacizumab-treated glioma patients and non-bevacizumab-treated controls that reported data on adverse vascular events. Four high-quality trials were finally included in the systematic review, scoring greater than or equal to 7/8 on the Newcastle-Ottawa Scale. Three trials provided sufficient data for four meta-analytical comparisons between bevacizumab-treated and control groups of newly diagnosed glioblastoma multiforme (GBM) patients: all-cause discontinuation, thrombocytopenia, deep vein thrombosis (DVT), and pulmonary embolism. None of these adverse outcomes were found to be significantly different between bevacizumab-treated and control groups (P > 0.05); however, there was a trend toward significance with regard to bevacizumab therapy and the risk of pulmonary embolism (P = 0.07). As there was a trend toward significance with regard to bevacizumab therapy and the risk of pulmonary embolism, anticoagulation may be advisable in certain newly diagnosed adult GBM patients who display a history of thromboembolism and/or more serious risk factors for thromboembolic events.