Vertebral and Carotid Artery Stenosis after Irradiation Both Raise Ischemic Stroke Risk in Head and Neck Cancer Patients

PurposeTo study the risk of ischemic stroke (IS) following carotid (CAS) or vertebral artery stenosis (VAS) in head and neck cancer (HNC) patients after radiation therapy (RT). MethodsWe included HNC patients who received RT between 2010 and 2023. They underwent regular head and neck imaging monitoring to evaluate cancer recurrence at the department of radiation-oncology and vascular examinations at the department of neurology. Patients were initially divided into nasopharyngeal carcinoma (NPC) and non-NPC groups. The primary outcome was the occurrence of IS after RT, and the secondary outcomes included the development of >50% CAS or >50% VAS after RT. Cox regression and Kaplan-Meier analyses were conducted to compare the outcomes of the study groups. Further analysis was conducted based on the presence or absence of >50% CAS or >50% VAS during the follow-up period. ResultsOf the 1,423 HNC patients, 19%, 6.8%, and 2.3% developed >50% CAS, >50% VAS, and IS during a 58-month follow-up. Compared with the NPC group, the non-NPC group exhibited a higher incidence of >50% CAS (25.4% vs. 10.7%, p<0.001) and >50% VAS (8.8% vs. 4.3%, p<0.001), but similar risks of IS. In patients with HNC, >50% CAS (adjusted hazard ratio [HR]=3.21, 95% confidence interval [CI]=1.53-6.71), and >50% VAS (adjusted HR=2.89, 95% CI=1.28-6.53) were both the independent predictors of IS. In the patients with NPC, >50% CAS was an independent predictor of anterior circulation IS (adjusted HR=4.39, 95% CI=1.17-16.47). By contrast, >50% VAS emerged as a predictor of posterior circulation IS in both the NPC (adjusted HR=15.02, 95% CI=3.76-60.06) and non-NPC groups (adjusted HR=13.59, 95% CI=2.21-83.46). ConclusionHNC patients with >50% CAS or >50% VAS after RT had an increased risk of IS within their corresponding vascular territory. CAS is a major predictor of IS in NPC patients, whereas VAS is a major predictor of IS in both NPC and non-NPC patients.