title: Incidence of carotid stenosis in nasopharyngeal carcinoma patients after radiotherapy.
abstract: BACKGROUND
  Radiation-induced carotid stenosis in patients with head and neck tumors can cause significant mortality and morbidity. This study examined the incidence of stenosis in the extracranial carotid arteries of nasopharyngeal carcinoma patients after radiotherapy.
  
  
  METHODS
  The extracranial carotid arteries of 71 (53 male and 18 female; mean age of 53.6 years) postradiation patients with nasopharyngeal carcinoma were examined with color Doppler ultrasound. The distribution of the arterial stenosis and the degree of stenosis were documented. The results were compared with the control group, which comprised 51 newly diagnosed nasopharyngeal carcinoma patients (35 male and 16 female, mean age of 48.8 years) before radiotherapy. Incidences of risk factors for arterial stenosis such as hypertension, smoking, and hypercholesterolemia also were studied in these two groups.
  
  
  RESULTS
  There was no significant difference in the incidence of risk factors between the two groups. Arterial stenosis was, however, more common in the postradiation group than the preradiation group (56 of 71 vs. 11 of 51). The common/internal carotid arteries (CCA/ICA) were most commonly involved (55 of 71 vs. 11 of 51; P < 0.01), followed by the external carotid artery (ECA) (32 of 71 vs. 1 of 51; P < 0.01) and vertebral artery (VA; 5 of 71 vs. 0; P = 0.069). Significant stenosis (> 50% reduction of luminal diameter) was only found in the postradiation group (21 of 71 in CCA/ICA, 11 of 71 in ECA, 4 of 71 in VA).
  
  
  CONCLUSIONS
  This study showed that radiation could cause significant carotid stenosis. Ultrasound examinations for these patients therefore are necessary for early detection and possible intervention of this late radiation-induced complication.
authors.affiliation: Department of Diagnostic Radiology and Organ Imaging, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR China. wynnie@cuhk.edu.hk
authors.forename: W W
authors.initials: WW
authors.lastname: Lam
authors.forename: S F
authors.initials: SF
authors.lastname: Leung
authors.forename: N M
authors.initials: NM
authors.lastname: So
authors.forename: K S
authors.initials: KS
authors.lastname: Wong
authors.forename: K H
authors.initials: KH
authors.lastname: Liu
authors.forename: P K
authors.initials: PK
authors.lastname: Ku
authors.forename: H Y
authors.initials: HY
authors.lastname: Yuen
authors.forename: C
authors.initials: C
authors.lastname: Metreweli
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000532:radiotherapy*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D011878:Radiotherapy / Q000009:adverse effects*; D012307:Risk Factors; D018615:Ultrasonography, Doppler, Color