title: Reliability of post-chemoradiotherapy F-18-FDG PET/CT for prediction of locoregional failure in human papillomavirus-associated oropharyngeal cancer.
abstract: OBJECTIVE
  Although widely adopted, the accuracy of post-chemoradiotherapy (CRT) 18F-fluorodeoxygluocose positron emission tomography/computed tomography (PET/CT) for predicting locoregional failure (LRF) in human papillomavirus-related (HPV+) oropharyngeal cancer (OPC) remains poorly characterized. We assessed the predictive value of 3-month PET/CT response for LRF in this population.
  
  
  METHODS
  101 consecutive patients with stage III-IV HPV+ OPC who underwent definitive CRT with pre-treatment and 3-month post-CRT PET/CT at our institution from 3/2005-3/2011 were included. 3-month PET/CT response was re-classified as complete-response (CR), near-CR, or incomplete-response (<CR) for each the primary site and neck. Accuracy of 3-month PET/CT for predicting local failure (LF) and regional failure (RF) was analyzed.
  
  
  RESULTS
  Among 98 patients with an evaluable primary tumor, LF occurred in 2/67 patients with CR, 0/20 with near-CR, and 1/11 with <CR on 3-month PET/CT. Of 98 node-positive patients, RF occurred in 6/80 with CR, 2/9 with near-CR, and 0/7 with <CR in the neck at 3 months. Sensitivity and positive predictive value (PPV) of 3-month PET/CT response for LF and RF were low (0-33%), despite a high negative predictive value (NPV) (91-98%). SUVmax thresholds or % change did not improve the accuracy of 3-month PET/CT. Use of additional PET/CT surveillance after 3 months in 67 patients accurately detected both LF (96%) and RF (97%).
  
  
  CONCLUSIONS
  In the largest study to-date of PET/CT response assessment in HPV+ OPC, 3-month PET/CT response demonstrated high NPV for LRF, though with disappointing sensitivity and PPV. Subsequent PET/CT surveillance showed potential utility for early detection of LRFs.
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States. Electronic address: jvainsh@med.umich.edu.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Vainshtein
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Spector
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Stenmark
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Carol R
authors.initials: CR
authors.lastname: Bradford
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Gregory T
authors.initials: GT
authors.lastname: Wolf
authors.affiliation: Division of Hematology Oncology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Francis P
authors.initials: FP
authors.lastname: Worden
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Chepeha
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: McHugh
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Thomas
authors.initials: T
authors.lastname: Carey
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Ka Kit
authors.initials: KK
authors.lastname: Wong
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Avraham
authors.initials: A
authors.lastname: Eisbruch
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D009959:Oropharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy; D027383:Papillomaviridae; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Chemoradiotherapy; Human papillomavirus; Metabolic response; PET surveillance; PET/CT