title: PET-CT vs contrast-enhanced CT: what is the role for each after chemoradiation for advanced oropharyngeal cancer?
abstract: OBJECTIVE
  The aim of our study was to assess the utility of positron emission tomography (PET) and 2 fluoro-2-deoxy-D-glucose coupled with neck CT compared with contrast-enhanced CT in predicting persistent cancer either at the primary site or cervical lymphatics in patients with oropharyngeal cancer treated with concurrent chemoradiation
  
  
  METHODS
  Thirty consecutive patients underwent clinical examination, PET-CT, and contrast-enhanced CT to assess response after the completion of the treatment. The outcome variable was positive tissue diagnosis or negative disease at 6 months. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for the primary site as well as cervical disease.
  
  
  RESULTS
  Contrast-enhanced CT alone showed the best accuracy in detecting disease at the primary site after treatment (85.7%). Accuracy in evaluating residual tumor in the cervical lymphatics for contrast-enhanced CT and PET-CT was 59.3% and 74.1%, respectively. For evaluating the neck, PET-CT and contrast-enhanced CT demonstrated 100% NPV, but the PPV was 36.3% and 26.6%, respectively.
  
  
  CONCLUSIONS
  In this preliminary study, PET-CT seems to be superior to contrast-enhanced CT in predicting persistent disease in the neck after chemoradiation for oropharyngeal or unknown primary cancer, but not at the primary site. However, the possibility of a false-positive result in the neck remains high, and thus overtreatment may result. Even more concerning are the false-negative results. Larger, prospective studies will be important in defining the role of PET-CT in obviating the need for salvage neck dissections after chemoradiation.
authors.affiliation: Department of Otolaryngology, Emory University School of Medicine, Emory Otolaryngology, 1365A Clifton Rd NE, Ste 2315A, Atlanta, GA 30322, USA. amy.chen@emory.edu
authors.forename: Amy Y
authors.initials: AY
authors.lastname: Chen
authors.forename: Isabel
authors.initials: I
authors.lastname: Vilaseca
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Hudgins
authors.forename: David
authors.initials: D
authors.lastname: Schuster
authors.forename: Ragheev
authors.initials: R
authors.lastname: Halkar
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000628:therapy; D003287:Contrast Media; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging; D018365:Neoplasm, Residual; D009959:Oropharyngeal Neoplasms / Q000175:diagnosis* / Q000628:therapy; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D018714:Radiotherapy, Adjuvant; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18