Stroke is the second most common neurological complication in people with cancer, trailing only metastatic disease in the nervous system, yet the mechanism behind many of these events has long remained murky. A new systematic review published in the Journal of Neurology brings together the largest body of evidence to date on stroke driven by cancer-associated coagulopathy, a hypercoagulable state induced by malignancy itself. Drawing on 82 studies identified through a PRISMA 2020-compliant search of PubMed/MEDLINE, Scopus, the Cochrane Library and Embase covering the years 2000 to 2025, the review paints a detailed picture of an entity that is biologically distinct, radiologically recognizable and dangerously underdiagnosed. The authors, led by Carlota Jauregui Larrañaga of Hospital Universitario Donostia in Spain, argue that recognizing this syndrome earlier could meaningfully alter a prognosis that is currently among the bleakest in stroke medicine.
The epidemiological data assembled in the review are striking. Active cancer is present in roughly 5 to 10 percent of patients presenting with ischemic stroke, a proportion that rises among those with embolic stroke of undetermined source, the cryptogenic category in which no conventional mechanism can be identified. In 3 to 5 percent of such patients, the stroke actually precedes the cancer diagnosis by up to two years, making it the first clinical manifestation of an occult malignancy. Occult cancer is detected in about 5.3 percent of patients with embolic stroke of undetermined source, with the highest detection rate occurring in the early period after the stroke, at 14.3 per 1,000 person-months. Among cancer patients who do stroke, cancer-associated coagulopathy is the most frequent cause, accounting for 39.8 percent of cases, while traditional mechanisms such as large-artery atherosclerosis and cardioembolism from atrial fibrillation are comparatively less common.
Timing emerges as one of the most consistent signatures of the condition. The risk of hypercoagulability-related stroke peaks within the first six months after a cancer diagnosis, and many patients have already reached metastatic disease by the time the stroke occurs. Arterial thromboembolism more broadly shows a characteristic temporal pattern, with incidence peaking in the first year after cancer diagnosis, and stroke represents the majority of these arterial events at 71.6 percent. Although the risk declines after the first year, it remains elevated above that of the general population for as long as a decade. Histologically, adenocarcinoma dominates, with lung and pancreatic cancer most frequently implicated, followed by colorectal, breast and prostate malignancies. The interval between cancer diagnosis and stroke is particularly short in pancreatic and colorectal cancer, underscoring their especially potent thrombotic potential.
The pathophysiology described in the review is a layered interplay of tumor biology and hemostasis. Adenocarcinomas produce mucin, a heavily glycosylated molecule that, although largely cleared by the liver, can engage the adhesion molecules P-selectin and L-selectin to trigger the formation of platelet-rich microthrombi. Tumor cells also overexpress tissue factor, a transmembrane receptor that activates the coagulation cascade through the extrinsic pathway, and this expression is upregulated by oncogenic events such as inactivation of the p53 tumor suppressor and activating mutations in the K-ras oncogene. More recently, alterations in K-ras and the STK11 tumor suppressor gene have been linked to arterial thromboembolism risk, with hazard ratios of 2.22 and 3.48 respectively for stroke among individuals carrying versus lacking these alterations. A recent in vitro study in human pancreatic cancer cell lines further showed that thrombosis induced by tissue factor-expressing microvesicles depends predominantly on coagulation factors VIII and IX, with von Willebrand factor playing a lesser role.
Beyond mucins and tissue factor, the review highlights two additional mechanisms that have reshaped understanding of cancer-driven thrombosis. Circulating extracellular vesicles secreted by tumor cells have been measured by flow cytometry, and levels of cancer cell-derived vesicles are higher in patients with cancer-related stroke than in other groups, correlating with D-dimer levels but not with vesicle-associated tissue factor, which points to prothrombotic pathways beyond the canonical tissue factor route. In vitro experiments also found that vesicles from adenocarcinoma cell lines shorten clotting times more than those from squamous cell carcinoma, consistent with the clinical predominance of adenocarcinoma. Separately, neutrophil extracellular trap formation, or NETosis, has emerged as a key mediator: cancers sensitize peripheral neutrophils toward NET release via granulocyte colony-stimulating factor, and in stroke patients with cancer, NET-specific biomarkers such as plasma DNA, nucleosomes and citrullinated histone H3 are significantly elevated and correlate with D-dimer and thrombin-antithrombin complex levels. A post-mortem histopathological study even demonstrated widespread microvascular thrombosis in the brain, with H3Cit-positive cells embedded in multiple cerebral thrombi.
Clots physically retrieved from patients during thrombectomy provide direct confirmation of this biology. Thrombi from stroke patients with active cancer are platelet-rich and erythrocyte-poor, a composition most pronounced in those with non-bacterial thrombotic endocarditis, and immunohistochemical analysis shows significantly higher content of von Willebrand factor and citrullinated histone H3 in clots from patients with cancer. Proteomic studies have added further markers, identifying elevated levels of proteins associated with active cancer and immune responses, such as IGHG1 and vitronectin, in cancer-related clots. This distinctive composition has a practical radiological consequence: the absence of the susceptibility vessel sign on susceptibility-weighted imaging in patients with large-vessel occlusion is associated with active cancer, with a reported sensitivity of 27 percent and specificity of 85 percent, reflecting the fibrin- and platelet-heavy, red-cell-poor nature of the thrombus.
On brain imaging, the review identifies a pattern that should raise immediate suspicion. The hallmark of cancer-associated coagulopathy stroke is multiple ischemic lesions spanning more than two vascular territories on diffusion-weighted MRI, with microembolic dispersion seen in 78 percent of patients and prior silent infarcts in half. The most specific finding is the so-called three territories sign, defined by simultaneous bilateral lesions in three vascular territories spanning both anterior and posterior circulation. In the absence of infective endocarditis, this sign is highly specific for cancer-related stroke, and among patients with three-territory infarcts and no identifiable embolic source, approximately 75 percent of cases are malignancy-related. The number of affected territories independently predicts occult malignancy in cryptogenic stroke. Cortical and subcortical regions are most frequently affected, followed by the cerebellar hemispheres and corpus callosum, while deep structures and the brainstem are rarely involved.
Biomarker evidence converges on D-dimer as the single most useful test, despite its lack of specificity. Proposed diagnostic thresholds vary, with one study suggesting a cutoff of 5.5 micrograms per milliliter yielding 99.7 percent specificity and 92.9 percent positive predictive value, and a later study proposing 2.785 micrograms per milliliter with 50.9 percent sensitivity and 98.5 percent specificity. The authors caution, however, that different analytical platforms and reporting units, fibrinogen-equivalent versus D-dimer units, preclude a universal cutoff. D-dimer remains the only biomarker consistently associated with recurrent stroke and mortality in this population, and elevated levels after anticoagulant therapy predict early recurrence. Supporting markers include C-reactive protein above 20 milligrams per liter and fibrinogen above 600 milligrams per deciliter, both highly specific for occult malignancy in cryptogenic stroke, along with CA-125, elevated neutrophil-to-lymphocyte ratio above 15, and transcranial Doppler microembolic signals, though the latter show limited specificity. The NORSTROKE score, combining age, D-dimer, hemoglobin and smoking status, offers a probabilistic approach, estimating a 53 percent probability of active cancer in a patient under 75 with cryptogenic stroke, D-dimer above 3 milligrams per liter, hemoglobin below 12 grams per deciliter and a smoking history.
Treatment remains the weakest link in the evidence chain. Low-molecular-weight heparin and direct oral anticoagulants are the most commonly used secondary prevention strategies, with low-molecular-weight heparin generally preferred in gastrointestinal malignancies because of the higher bleeding risk of direct oral anticoagulants in that setting, while vitamin K antagonists are less effective. Comparative studies have shown broadly similar outcomes between agents: enoxaparin versus aspirin, direct oral anticoagulants versus enoxaparin, apixaban versus aspirin in a post hoc analysis of the ARCADIA trial, and oral edoxaban versus subcutaneous enoxaparin all failed to show significant differences in major bleeding, thromboembolism or survival. A recent retrospective study found no mortality or recurrence difference between anticoagulant and antiplatelet therapy, and a 2026 American Heart Association scientific statement concluded there is insufficient evidence to choose between anticoagulation and antiplatelet therapy for this indication. Current guidelines for cancer-associated thrombosis recommend at least three to six months of anticoagulation, extended when cancer remains active.
The prognosis statistics explain why the authors frame this as an urgent, underrecognized problem. Thirty-day mortality ranges from 25 to 50 percent, compared with 14 percent in stroke patients without cancer, and more than half of deaths occur within six months. The median modified Rankin Scale score at discharge is 3, and at three months 75.6 percent of patients remain at least moderately disabled. Recurrence rates reach 13.6 percent, roughly three times that of patients without cancer, with cumulative rates of 7 percent at one month and 16 percent at six months. When stroke is the first manifestation of occult malignancy, median survival is only 58 days, and median survival in cancer patients with cryptogenic stroke ranges from 62 to 365 days, versus 590 days for stroke of other causes. In patients with non-bacterial thrombotic endocarditis, up to 90 percent die or suffer recurrent stroke within six months. The review’s authors acknowledge limitations, including the predominance of retrospective observational data, the absence of prospective protocol registration, marked heterogeneity that prevented meta-analysis, and language restrictions to English and Spanish. They call for prospective multicenter cohorts, standardized D-dimer assays, external validation of the NORSTROKE score and randomized trials comparing low-molecular-weight heparin, direct oral anticoagulants and antiplatelet therapy. As cancer incidence rises and survival improves, they warn, the burden of this devastating stroke subtype will only grow, making earlier recognition and personalized antithrombotic strategies a clinical imperative.
Subject of Research: Ischemic stroke caused by cancer-associated coagulopathy, including its epidemiology, mechanisms, biomarkers, imaging features and treatment
Article Title: Stroke secondary to cancer-associated coagulopathy: a systematic review
Article References: Stroke secondary to cancer-associated coagulopathy: a systematic review. (n.d.). https://doi.org/10.1007/s00415-026-14119-y
Image Credits: AI Generated
DOI: 10.1007/s00415-026-14119-y
Keywords: stroke, cancer-associated coagulopathy, Trousseau syndrome, adenocarcinoma, D-dimer, hypercoagulability, three territories sign, anticoagulation, low-molecular-weight heparin, direct oral anticoagulants, neutrophil extracellular traps, tissue factor
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Nathaniel Bowman. (September 21, 2026). Cancer Can Trigger Strokes Through Hidden Blood Clotting, Major Review Finds. Scienmag. https://scienmag.com/cancer-can-trigger-strokes-through-hidden-blood-clotting-major-review-finds/
Nathaniel Bowman. “Cancer Can Trigger Strokes Through Hidden Blood Clotting, Major Review Finds.” Scienmag, 21 September 2026, https://scienmag.com/cancer-can-trigger-strokes-through-hidden-blood-clotting-major-review-finds/. Accessed 21 September 2026.
Nathaniel Bowman. “Cancer Can Trigger Strokes Through Hidden Blood Clotting, Major Review Finds.” Scienmag. September 21, 2026. https://scienmag.com/cancer-can-trigger-strokes-through-hidden-blood-clotting-major-review-finds/
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