Carotid stenosis after radiotherapy for nasopharyngeal carcinoma.

OBJECTIVE

To determine the prevalence and risk factors for radiation-induced carotid stenosis in patients with malignant neoplasms of the head and neck.

DESIGN

Prospective cross-sectional screening of extracranial carotid stenosis by color-flow duplex ultrasonography with an analysis of demographic and comorbid risk factors.

SETTING

Tertiary oncology and vascular referral center.

PATIENTS

The study included 96 consecutive patients (75 men and 21 women; mean age, 53.6 years) who had undergone cervical radiotherapy (RT) for nasopharyngeal carcinoma more than 12 months ago. The mean post-RT interval was 79.9 months. Fourteen patients had cerebrovascular symptoms. A group of 96 healthy individuals were used as controls.

MAIN OUTCOME MEASURES

Internal carotid stenosis and common carotid artery stenosis were classified by duplex ultrasonography into moderate (30%-69%), severe (70%-99%), and totally occlusive.

RESULTS

Internal carotid artery stenosis of 70% or more was detected in 14 arteries in 12 patients (6 occlusions). Common carotid artery stenosis of 70% or more was found in 11 arteries in 9 patients (4 occlusions). Overall, 15 patients (16%) had critical stenosis in their common or internal carotid arteries, and another 20 (21%) had stenosis in the moderate range. Critical carotid stenosis was not present in any of the control subjects. Severe post-RT carotid stenosis was associated with age (P = .003), smoking (P = .004), heart disease (P<.001), no prior oncological surgery (P<.001), cerebrovascular symptoms (P<.001), and interval from RT (P<.001). Smoking, interval from RT, cerebrovascular symptoms, and no head and neck surgery were significant independent predictors for severe carotid stenosis on multivariate logistic regression analysis.

CONCLUSIONS

Patients who undergo irradiation of the head and neck for more than 5 years have a higher risk of developing significant carotid stenosis (relative risk, 15), and routine duplex ultrasound screening is recommended.