Focused high-risk population screening for carotid arterial stenosis after radiation therapy for head and neck cancer

Abstract

Background Cervical radiation for head and neck cancer has been associated with an increased incidence of carotid arterial stenosis. Modern radiation therapy delivers higher doses with increasing long-term survival. Accordingly, the prevalence of radiation-associated carotid stenosis may be higher than previously reported. Phase I of this prospective study was to establish the prevalence of carotid artery stenosis after high-dose cervical radiation. Methods From a prospectively maintained database, we identified patients who had received cervical high-dose radiotherapy (minimum 5,500 cGy). All patients were screened with bilateral carotid arterial duplex ultrasonography. We defined disease as “normal or mild” if the carotid stenosis was <50%, and “significant” if >50%. The relationship between standard demographic risk factors and screening outcomes was then analyzed. Results Screening was performed in 40 patients (mean age 68.2 years, range 26 to 87). Patients received a mean cumulative radiation dose of 6,420 cGy (range 5,500 to 7,680), with a mean duration of 10.2 years since their last radiation treatment. Sixteen patients (40%) had significant carotid artery stenosis. Patients with and without significant stenosis were comparable in terms of age, radiation dose, tobacco use, comorbidities, and postradiation interval ( P = not significant). Six patients (15%) had unilateral complete carotid occlusion and 6 patients (15%) had significant bilateral carotid stenosis. Three patients (7.5%) had sustained a previous stroke after radiation therapy. Conclusions The prevalence of carotid arterial disease in patients with prior cervical radiation therapy is clinically significant and warrants aggressive screening as part of routine preradiation and postradiation care. Focused screening of this high-risk population may be cost effective and medically beneficial in terms of risk factor modification and stroke prevention, and will be examined in phase II of this study.