title: Radiologic Differences between Human Papillomavirus-Related and Human Papillomavirus-Unrelated Oropharyngeal Carcinoma on Diffusion-Weighted Imaging.
abstract: OBJECTIVE
  Human papilloma virus-related oropharyngeal carcinoma (HPV+ OPC) is a unique entity compared to HPV-unrelated (HPV-) OPC. Previous studies were inconclusive regarding the differences between HPV+ and HPV- OPCs on diffusion-weighted imaging (DWI). This study sought to determine if there is an association between HPV status and apparent diffusion coefficient (ADC) values as an imaging biomarker in OPCs.
  
  
  METHODS
  OPC patients with pretreatment MRI including DWI were retrospectively reviewed and analyzed as a blinded, controlled cohort. HPV status was biopsy-ascertained with p16 staining. ADC values were determined by placing the largest possible circular region of interest in solid portions of primary tumors and/or metastatic lymph nodes. Necrotic and cystic portions were excluded.
  
  
  RESULTS
  Twenty-eight HPV+ and 12 HPV- patients were included. Adjusted for age and sex, ADC values were significantly lower in HPV+ OPC primary tumors (p = 0.013) and lymph node metastases (p = 0.013). The area under the curve (AUC) was 0.85 and 0.90, respectively. A model with a linear combination of the 2 variables yielded an AUC of 0.92.
  
  
  CONCLUSIONS
  ADC values were significantly lower in both the primary tumors and lymph node metastases in HPV+ OPCs compared to HPV- OPCs. These results confirm the results of prior studies.
authors.affiliation: Department of Medical Imaging, University of Toronto, Toronto, ON, Canada.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Chan
authors.forename: Kevin
authors.initials: K
authors.lastname: Higgins
authors.forename: Danny
authors.initials: D
authors.lastname: Enepekides
authors.forename: Ian
authors.initials: I
authors.lastname: Poon
authors.forename: Sean P
authors.initials: SP
authors.lastname: Symons
authors.forename: Rahim
authors.initials: R
authors.lastname: Moineddin
authors.forename: Ilan
authors.initials: I
authors.lastname: Weinreb
authors.forename: Omid
authors.initials: O
authors.lastname: Shearkhani
authors.forename: Amy
authors.initials: A
authors.lastname: Chen
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Beelen
authors.forename: Aimee
authors.initials: A
authors.lastname: Chan
authors.forename: Pejman Jabehdar
authors.initials: PJ
authors.lastname: Maralani
mesh_terms: D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000821:virology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009959:Oropharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000821:virology*; D027383:Papillomaviridae; D030361:Papillomavirus Infections / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology; D012189:Retrospective Studies