Background Fibrin and platelet (FP)-rich clots have been shown to be associated with cancer-related stroke. This study aims to investigate the prognostic role of thrombus composition in clinical outcomes among cancer patients who experienced stroke and received endovascular thrombectomy (EVT).

Methods We included acute ischemic stroke patients who underwent EVT between March 2015 and November 2021. These patients were categorized into three groups: those with active cancer, those with non-active cancer, and those without cancer. The percentages of FP in clots were quantified under hematoxylin and eosin staining. The primary outcome was defined as any stroke recurrence or mortality within 90 days following the index stroke event.

Results A total of 420 patients with retrieved clots were included in the study. This cohort comprised 50 patients with active cancer, 23 patients with non-active cancer, and 347 patients without cancer. The percentage of FP was significantly higher in thrombi retrieved from patients with active cancer compared with the other two groups. Patients in the active cancer group exhibited a higher rate of the primary outcome compared with the other groups. After adjusting for clinical variables, a higher percentage of FP in thrombi remained significantly associated with the primary outcome in the active cancer group (adjusted odds ratio (aOR) =1.03 (1.00–1.06), P=0.028), but not in the other two groups.

Conclusion Among stroke patients receiving EVT, thrombi with a higher percentage of FP not only identify individuals with active cancer but also predict stroke recurrence or mortality within 90 days.