title: Carotid stenosis after radiotherapy for nasopharyngeal carcinoma.
abstract: OBJECTIVE
  To determine the prevalence and risk factors for radiation-induced carotid stenosis in patients with malignant neoplasms of the head and neck.
  
  
  METHODS
  Prospective cross-sectional screening of extracranial carotid stenosis by color-flow duplex ultrasonography with an analysis of demographic and comorbid risk factors.
  
  
  METHODS
  Tertiary oncology and vascular referral center.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
authors.affiliation: Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, China.
authors.forename: S W
authors.initials: SW
authors.lastname: Cheng
authors.forename: A C
authors.initials: AC
authors.lastname: Ting
authors.forename: L K
authors.initials: LK
authors.lastname: Lam
authors.forename: W I
authors.initials: WI
authors.lastname: Wei
mesh_terms: D017536:Carotid Artery, Common; D002343:Carotid Artery, Internal; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013997:Time Factors; D018615:Ultrasonography, Doppler, Color