Predictors of carotid artery stenosis after radiotherapy for head and neck cancers

Objective: To study the prevalence of and risk factors associated with carotid artery stenosis (CAS) after radiotherapy (RT) for head and neck cancer. Methods: Design of study: Prospective, cross-sectional study. Setting: Patients recruited from a hospital Radiation-Oncology department. Subjects: From March 2002 to August 2006, 290 consecutive head and neck cancer patients were enrolled in this study. One hundred ninety-two of these patients had previously undergone RT (RT group) and 98 had no RT (control group). Intervention: After detecting CAS by carotid duplex sonography, the severity of CAS was evaluated by a bilateral plaque scoring system. Main outcome measure: CAS score. Results: There were no differences in age or gender between the two groups. The RT group had a significantly higher plaque score than the non-irradiated group (P < .05). Multiple regression analysis of the 290 head and neck cancer patients revealed that bilateral plaque score was significantly correlated with age, hyperlipidemia, and RT. Multiple regression analysis was performed in the RT group alone with patients 41-50 years old serving as the reference group. This analysis showed that in RT patients > 50 years old, age was inversely correlated with plaque score; however, in RT patients ≤ 41 years old, age was positively correlated with plaque score. Conclusion: In head and neck cancer, the high post-treatment incidence of radiation-induced CAS indicates the importance of regular examination of the carotid duplex and early antiplatelet prophylaxis. Different age groups may require different irradiation strategies to prevent radiation-induced CAS.