Arterial stiffness as an ultrasound biomarker of radiation-induced carotid artery disease

Background: Radiation-induced carotid artery disease (RICAD) is an important issue in head and neck cancer (HNC) survivors after radiotherapy (RT). The risk of cerebrovascular disease in these patients is doubled. The aim of this study was to assess the effect of RT on carotid artery stiffness in HNC patients. Patients and methods: Conventional arterial stiffness parameters were measured in a total of 50 HNC survivors treated with RT for at least 5 years and compared to 50 unirradiated HNC patients. Elastic modulus (Ep) and Beta stiffness index (β) were measured in proximal, mid and distal common carotid artery (CCA). Results: The mean age of the subjects was 68±9 years (range: 44-84) in the irradiated group and 67±10 years (range: 45-85) in the control group. The RT group was treated with a mean radiation exposure of 60.3±6.7 Gy (range: 44-72) in the neck. Carotid stiffness parameters showed significant group differences: Ep in the RT group was 2.329±1.222 vs 1.742±828 in the non-RT group (p=0.006) and β index in the RT group was 23±11 vs 15±8 in the non-RT group (p<0.001). Radiation-induced carotid stiffness was quantified and cervical exposure to RT increased Ep in 575 kPa (p=0.014) and β in 7 units (p<0.003). Conclusions: Ep and β index could be suitable ultrasound biomarkers of radiation-induced atherosclerosis in HNC survivors. Further prospective studies are needed to feature RICD in this setting.