Elevated risk of ischemic stroke after invasive cancer diagnosis: A nationwide population‐based study

BACKGROUND: Cancer and stroke are major causes of morbidity and mortality, with an increasing shared burden. This study aimed to provide population-based estimates of ischemic stroke (IS) risk after cancer diagnosis across multiple cancer sites and demographic subgroups. METHODS: A retrospective cohort study was conducted linking the Israel National Cancer and Stroke Registries. Residents ≥40 years old diagnosed with first invasive cancer during 2014-2021 were followed for first-ever IS within 1 year. IS risk was assessed using standardized incidence ratios (SIRs) and analyzed by cancer site, time since diagnosis, cancer stage, and demographic subgroups. One-year cumulative incidence was estimated with death as a competing event. RESULTS: Among 182,221 patients, the SIR for IS within 1 year after cancer diagnosis was 1.8 (95% confidence interval [CI], 1.7-1.9). Risk peaked during the first 3 months (SIR, 2.5; 95% CI, 2.2-2.7). The highest SIRs were observed for pancreatic (SIR, 5.9; 95% CI, 4.8-7.3) and lung (SIR, 3.9; 95% CI, 3.4-4.4) cancers. SIRs decreased with age from 3.6 (95% CI, 2.8-4.6) among adults 40-54 years old to 1.4 (95% CI, 1.3-1.6) among those ≥75 years old. SIRs increased with stage, from 1.2 (95% CI, 1.0-1.4) in localized disease to 2.8 (95% CI, 2.5-3.2) in metastatic disease. One-year cumulative incidence of IS was 0.62%, ranging from 0.30% in breast cancer to 1.62% in pancreatic cancer. CONCLUSIONS: The early period after cancer diagnosis represents a critical window of increased IS risk. Incorporating targeted cerebrovascular risk assessment into oncologic care may facilitate earlier identification of high-risk subgroups and support tailored prevention strategies.