Radiation effects on the intima-media thickness of the common carotid artery in post-radiotherapy patients with head and neck malignancy.

Background: Post-radiation large vessel injury has not received as much attention as microvascular irradiation injury. A few studies have shown that common carotid intima-media thickness (IMT) is increased after radiotherapy to the head and neck. However, in most of these studies, the irradiated subjects also had other major risk factors for atherosclerosis. In this study, irradiated subjects with major risk factors such as hypertension, diabetes, history of previous cerebrovascular accident and connective tissue disorder were excluded.
Objective: To show in a cross-sectional study if radiotherapy to the carotid area has any effect on the IMT of the common carotid artery.
Subjects and Methods: 13 patients with head and neck malignancies who had completed radiotherapy to the carotid region at least 1 year previously underwent ultrasound of the carotid artery. IMT measurements were compared with those of 13 healthy controls, matched for age, sex and race, with no history of radiotherapy.
Results: The irradiated subjects had significantly larger IMT measurements (mean 0.74 mm) than the non-irradiated subjects (mean 0.46 mm). The difference was significant (p<0.001) with a confidence interval of 95%.
Conclusions: This study shows that there is a measurable, significant (p<0.001) increase in IMT of the common carotid artery after radiotherapy for head and neck malignancy compared with non-irradiated matched controls. This knowledge is important for risk-benefit assessment of prophylactic or therapeutic neck irradiation. Increased awareness of this complication should provide an opportunity to intervene and prevent future cerebrovascular accidents in the majority of such patients.