Cerebrovascular events after head and neck radiation therapy: A systematic review and Meta-Analysis

Several studies have demonstrated increased risk of cerebrovascular events, including carotid stenosis, stroke & transient ischemic attack, following head and neck radiation therapy (RT) for head and neck cancer (HNC). This systematic review reports the incidence of cerebrovascular events (CVEs) and the relative rate (RR) of ischemic stroke in patients treated with RT compared to non-RT populations.

A comprehensive database search identified publications reporting the incidence or RR of CVEs following RT. Citations were retrieved, and data was extracted where appropriate. Risk of bias was assessed, and meta-analyses were conducted to present pooled estimates of the incidence of CVEs after RT and the RR of ischemic stroke.

2,598 citations were retrieved, of which 50 met criteria for inclusion. The incidence of carotid stenosis ranged from 0 %-40 % over median follow-up duration of 6-68 months (mean = 6-150 months). The incidence of ischemic stroke was 8.98 per 1,000 person-years (95 % CI: 4.66 - 17.30). The relative rate of ischemic stroke was higher in patients treated with radiation therapy with a HR of 1.33 (95 % CI: 1.21 - 1.45) when compared to a reference population (HR of 1) of those treated with surgery and a HR of 1.29 (95 % CI: 1.13 - 1.47) when compared to the general population as the reference group.

HNC patients face an increased risk of ischemic stroke following head and neck radiation therapy. The magnitude of this heightened risk remains elusive in the contemporary era of intensity-modulated radiation techniques and should be addressed in future studies.