title: A prospective study of the effects of irradiation on the carotid artery.
abstract: OBJECTIVE
  To prospectively assess the effects of irradiation on the carotid artery in patients with head and neck cancer, as a possibly relevant factor in cancer treatment planning.
  
  
  METHODS
  Prospective study from a tertiary care academic setting on university (22 patients) and Veterans Affairs (14 patients) hospital patients; 1-year follow-up, including comparison of study data with age-matched and sex-matched control subjects from epidemiological studies.
  
  
  METHODS
  Thirty-six patients with head and neck cancer who underwent therapeutic neck irradiation were examined by high-resolution ultrasound before and 1 year after treatment. Twelve patients were also studied at 2 years. Measurements included the intima-media thickness (IMT) of the carotid artery wall, the degree of stenosis as estimated from velocity measurements, and the presence and size of plaque.
  
  
  RESULTS
  The pretreatment carotid IMT at baseline was 0.68 mm and was comparable to age-matched and sex-matched control subjects. Significant increase in the IMT was observed on both the left (0.67 vs. 0.84 mm) and the right (0.7 vs. 0.87 mm) sides (P < .001) 1 year after irradiation. In 12 patients who completed 24 months of follow-up the carotid IMT continued to significantly increase statistically compared with that at the first year after treatment (left side, 0.79 vs. 0.85 mm, P = .037; right side, 0.79 vs. 0.95 mm, P = .014). Statistically significant thickening of the carotid wall developed in all 36 patients by 1 year. Two patients experienced post-treatment neurological events and an area of stenosis greater than 75%.
  
  
  CONCLUSIONS
  Neck irradiation significantly increases the thickness of the carotid wall during the first year after treatment--on average, 21 times more than in epidemiologically matched control volunteers. This phenomenon should be taken into consideration when planning treatment for the node-negative (NO) neck.
authors.affiliation: Department of Otolaryngology--Head and Neck Surgery, Loyola University of Chicago Medical Center, Maywood, Illinois, USA.
authors.forename: K
authors.initials: K
authors.lastname: Muzaffar
authors.forename: S L
authors.initials: SL
authors.lastname: Collins
authors.forename: N
authors.initials: N
authors.lastname: Labropoulos
authors.forename: W H
authors.initials: WH
authors.lastname: Baker
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000528:radiation effects*; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000528:radiation effects; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011832:Radiation Injuries / Q000000981:diagnostic imaging* / Q000209:etiology; D012039:Regional Blood Flow; D014463:Ultrasonography