Assessment of venous thromboembolism in adult diffuse-type gliomas: an experience of a quaternary center and a systematic review

Venous thromboembolism (VTE) is under-recognized in adult-type diffuse gliomas, and its overall frequency and determinants remain poorly defined. We carefully retrospectively examined 147 patients treated at a Brazilian quaternary neuro-oncology center during 2018–2023 and performed a PRISMA/SWiM systematic review of observational studies published since 2015. In the cohort, median age at diagnosis was 55 years (range 20–86); glioblastoma predominated (62%), followed by astrocytoma (22%) and oligodendroglioma (16%), respectively. VTE prevalence was 3.4% (5/147). One event arose in patients with IDH-wild-type glioblastoma, yielding a 5.6% incidence in this subgroup, whereas no thrombosis occurred in IDH-mutant oligodendroglioma or lower-grade astrocytoma. All five events occurred within 90 days of surgery, with pulmonary embolism accounting for three and lower-limb deep-vein thrombosis for two; cerebral venous thrombosis was not observed. Events clustered between 41 and 60 years and were evenly distributed by sex. The systematic review incorporated eight observational cohorts (n = 7779). Reported VTE incidence ranged from 6.2–31% in grade IV gliomas and from 1.4–5.2% in lower grades. Deep-vein thrombosis comprised 60% of events, pulmonary embolism 35%, and cerebral venous thrombosis 5%. Risk was higher with poor performance status, surgery > 4h, and bevacizumab exposure, whereas an IDH mutation reduced risk by about 70%. Median time from surgery to VTE diagnosis ranged between 21 and 90 days, and 30-day mortality after VTE varied from 7–15%. Large, prospective, multicenter, molecularly annotated glioma cohorts remain vital for thrombosis risk stratification and targeted prophylactic strategies. Clinical Trial Number: Not applicable