title: Do traditional risk stratification models for cerebrovascular events apply in irradiated head and neck cancer patients?
abstract: BACKGROUND
  Primary radical radiotherapy (RT) for head and neck cancer (HNC) often results in significant radiation dose to the carotid arteries.
  
  
  OBJECTIVE
  We assessed whether HNC patients are at increased risk of a cerebrovascular event primarily due to RT or other risk factors for atherosclerosis by (i) risk-stratifying patients according to validated QRISK-2 and QSTROKE scores and (ii) comparing the prevalence of carotid artery stenosis (CAS) in irradiated and unirradiated carotid arteries.
  
  
  METHODS
  HNC patients treated with an RT dose >50 Gy to one side of the neck ≥2 years previously were included.
  
  
  METHODS
  QRISK-2 (2014) and Q-STROKE (2014) scores were calculated. We compared the prevalence of CAS in segments of the common carotid artery on the irradiated and unirradiated sides of the neck.
  
  
  RESULTS
  Fifty patients (median age of 58 years (interquartile range (IQR) 50-62)) were included. The median QRISK-2 score was 10% (IQR 4.4-15%) and the median QSTROKE score was 3.4% (IQR 1.4-5.3%). For both scores, no patient was classified as high risk. Thirty-eight patients (76%) had CAS in one or both arteries. There was a significant difference in the number of irradiated arteries with stenosis (N = 37) compared with unirradiated arteries (N = 16) (P < 0.0001). There were more plaques on the irradiated artery compared with the unirradiated side - 64/87 (73.6%) versus 23/87 (26.4%), respectively (P < 0.001).
  
  
  CONCLUSIONS
  Traditional vascular risk factors do not play a role in radiation-induced carotid atherosclerosis. Clinicians should be aware that traditional risk prediction models may under-estimate stroke risk in these patients.
authors.affiliation: From the Head and Neck Unit, Department of Radiotherapy, The Royal Marsden Hospital, 203 Fulham Road, London SW3 6JJ, UK and chris.nutting@rmh.nhs.uk.
authors.forename: D M
authors.initials: DM
authors.lastname: Gujral
authors.affiliation: Department of Echocardiography, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.
authors.forename: B N
authors.initials: BN
authors.lastname: Shah
authors.affiliation: Department of Echocardiography, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.
authors.forename: N S
authors.initials: NS
authors.lastname: Chahal
authors.affiliation: Department of Echocardiography, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.
authors.forename: S
authors.initials: S
authors.lastname: Bhattacharyya
authors.affiliation: Department of Echocardiography, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.
authors.forename: R
authors.initials: R
authors.lastname: Senior
authors.affiliation: From the Head and Neck Unit, Department of Radiotherapy, The Royal Marsden Hospital, 203 Fulham Road, London SW3 6JJ, UK and.
authors.forename: K J
authors.initials: KJ
authors.lastname: Harrington
authors.affiliation: From the Head and Neck Unit, Department of Radiotherapy, The Royal Marsden Hospital, 203 Fulham Road, London SW3 6JJ, UK and.
authors.forename: C M
authors.initials: CM
authors.lastname: Nutting
mesh_terms: D002339:Carotid Arteries / Q000473:pathology / Q000528:radiation effects*; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D005260:Female; D006258:Head and Neck Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D011832:Radiation Injuries / Q000000981:diagnostic imaging*; D011879:Radiotherapy Dosage; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D014463:Ultrasonography