One-year cancer incidence following acute ischemic stroke: a retrospective propensity-matched multi-center cohort study

Acute ischemic stroke (AIS) and cancer share overlapping pathophysiologic mechanisms, and stroke survivors may face an elevated short-term risk of incident malignancy, but population-level estimates remain limited. We conducted a retrospective cohort study using the TriNetX US Collaborative Network to quantify the one-year incidence of new neoplasm diagnosis following AIS. Adults with first-ever AIS (ICD-10-CM I63.x; index date ≥ 2015) were compared with patients hospitalized for first-ever acute non-stroke neurological conditions and 1:1 propensity score matched on demographic and clinical covariates. After matching, both cohorts comprised 937,244 patients. AIS was associated with a higher one-year incidence of new neoplasm diagnosis (5.30% vs. 5.19%; RR 1.021, 95% CI 1.009–1.034; p < 0.001). Elevated incidence was observed for lung (RR 1.24, 95% CI 1.17–1.32), colorectal (RR 1.17, 95% CI 1.08–1.26), and thyroid cancers (RR 1.21, 95% CI 1.07–1.38), all persisting in a sensitivity analysis restricted to days 31–365. In a descriptive competing-risks analysis of the unmatched cohorts, the Aalen-Johansen one-year cumulative incidence of neoplasm was 6.65% in AIS and 5.14% in controls. These findings support consideration of prospective studies evaluating risk-stratified post-stroke cancer surveillance.