Abstract
Venous thromboembolism (VTE) remains a clinically relevant and impactful complication in patients with adult-type diffuse gliomas, and its overall frequency and determinants remain poorly defined. We retrospectively examined 147 patients with gliomas treated at a Brazilian quaternary neuro-oncology center during 2018–2023 and performed a Preferred Reporting Items for Systematic Reviews and Meta-Analysis/Synthesis without Meta-Analysis–based systematic review of observational studies (incorporating eight cohorts; N = 7779) published since 2015. The patients’ median age at diagnosis was 55 (range 20–86) years. Glioblastoma was the predominant glioma type (n = 91, 61.9%), followed by astrocytoma (n = 32, 21.8%) and oligodendroglioma (n = 24, 16.3%). VTE events occurred in 5 (3.4%) patients, 4 (80%) with isocitrate dehydrogenase (IDH)–wild-type glioblastoma (5.6% incidence within this subgroup) and 1 (20%) with IDH-mutant astrocytoma; no thrombosis was identified in patients with oligodendrogliomas. All five events (three pulmonary thromboembolism [PTE] and two lower-limb deep-vein thrombosis [DVT]) events) occurred within 6 months of surgery, clustered in patients aged between 41 and 60 years and evenly distributed by sex. Cerebral venous thrombosis (CVT) was not observed. In the systematic review, the VTE incidence rate was 6.2%–31% in grade 4 gliomas and 1.4%–5.2% in grades 2 and 3. DVT comprised 60% of thromboembolic events; PTE, 35%; and CVT, 5%. Poor performance status, a surgery duration of > 4 h, and bevacizumab exposure increased the risk for VTE, whereas IDH mutation reduced it by ~ 70%. The median time from surgery to VTE diagnosis was 21–90 days, and 30-day mortality after VTE was 7%–15%. Findings show that large, prospective, multicenter, molecularly annotated glioma cohorts remain vital for thrombosis risk stratification and targeted prophylactic strategy development. Clinical trial number: Not applicable. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10143-026-04299-6.