title: Predictors of the extent of carotid atherosclerosis in patients treated with radiotherapy for nasopharyngeal carcinoma.
abstract: OBJECTIVE
  To determine the predictors of the extent of carotid atherosclerosis in patients treated with radiotherapy (RT) for nasopharyngeal carcinoma (NPC).
  
  
  METHODS
  The present study investigated 129 post-RT NPC patients. Carotid atherosclerotic parameters, such as carotid intima-media thickness, carotid arterial stiffness and carotid plaque burden (plaque score, the presence of plaque and ≥50% stenosis) were assessed using ultrasonography. The association between carotid atherosclerotic parameters and nine potential predictors, including age, gender, post-RT duration, radiation dose, chemotherapy, diabetes mellitus, hypertension, hypercholesterolemia, and smoking, were determined using multiple regression. The cutoff values of age, post-RT duration and number of cardiovascular risk factors for the presence of carotid plaque or ≥50% carotid stenosis were analyzed using receiver operating characteristic (ROC) curve analysis. Multiple testing was corrected using Benjamini-Hochberg false discovery rate.
  
  
  RESULTS
  Age, post-RT duration and number of cardiovascular risk factors were significantly associated with carotid plaque burden (corrected P value, Pcor<0.05). Age of 44.5 years (sensitivity = 99.2% and specificity = 50%, Pcor<0.01) and post-RT duration of 8.5 years (sensitivity = 75.7% and specificity = 64.3%, Pcor<0.001) were the cutoff values for detecting carotid plaque, while post-RT duration of 13.5 years (sensitivity = 66.7% and specificity = 71.6%, Pcor<0.001) and 1.5 cardiovascular risk factors (sensitivity = 40.7% and specificity = 84.3%, Pcor<0.05) were the cutoff values for screening ≥50% carotid stenosis.
  
  
  CONCLUSIONS
  Age, post-RT duration and number of cardiovascular risk factors are significant predictors of carotid atherosclerosis in post-RT NPC patients. Post-RT NPC patients, who are at least 45 years old, with post-RT duration of 9 years or above, and/or have ≥2 cardiovascular risk factors, are more susceptible to carotid atherosclerosis.
authors.affiliation: Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
authors.forename: Chuang
authors.initials: C
authors.lastname: Yuan
authors.affiliation: Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
authors.forename: Vincent W C
authors.initials: VW
authors.lastname: Wu
authors.affiliation: Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
authors.forename: Shea Ping
authors.initials: SP
authors.lastname: Yip
authors.affiliation: Department of Clinical Oncology, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
authors.forename: Dora L W
authors.initials: DL
authors.lastname: Kwong
authors.affiliation: Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
authors.forename: Michael
authors.initials: M
authors.lastname: Ying
mesh_terms: D000328:Adult; D000367:Age Factors; D002277:Carcinoma; D002339:Carotid Arteries / Q000473:pathology / Q000528:radiation effects*; D002340:Carotid Artery Diseases / Q000209:etiology* / Q000473:pathology; D059168:Carotid Intima-Media Thickness; D016893:Carotid Stenosis / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000150:complications / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000473:pathology; D012044:Regression Analysis; D012307:Risk Factors; D059289:Vascular Stiffness