title: Post-treatment PET/CT and p16 status for predicting treatment outcomes in locally advanced head and neck cancer after definitive radiation.
abstract: OBJECTIVE
  To retrospectively review post-treatment (post-tx) FDG-PET/CT scans in patients with advanced head and neck squamous cell carcinoma (HNSCC) and known p16 status, treated with definitive (chemo)radiation (RT).
  
  
  METHODS
  A total of 108 eligible patients had N2A or greater HNSCC treated with chemoRT from August 1, 2008, to February 28, 2015, with post-tx PET/CT within 6 months after RT. Kaplan-Meier curves, log-rank statistics, and Cox proportional hazards regression were used for statistical analysis.
  
  
  RESULTS
  Median follow-up was 2.38 years. Sixty-eight (63.0%) patients had p16+ and 40 (37.0%) had p16- status. Two-year overall survival and recurrence-free survival were 93.4% and 77.8%, respectively. The negative predictive value (NPV) of PET/CT for local recurrence (LR) was 100%. The NPV for regional recurrence (RR) was 96.5% for all patients, 100% for p16+ patients, and 88.5% for p16- patients. The positive predictive value (PPV) of PET/CT for recurrence was 77.3% for all patients, 50.0% for p16+, and 78.6% for p16-. The PPV for LR was 72.7% for all patients, 50.0% for p16+ patients, and 72.7% for p16- patients. The PPV for RR was 50.0% for all patients, 33% for p16+, and 66.6% for p16-. Post-tx PET/CT and p16 status were independent predictors of recurrence-free survival (p < 0.01).
  
  
  CONCLUSIONS
  Post-tx PET/CT predicts treatment outcomes in both p16 + and p16- patients, and does so independently of p16 status. P16- patients with negative PET have a 10% risk of nodal recurrence, and closer follow-up in these patients is warranted.
authors.affiliation: Department of Radiation Oncology, Case Western Reserve University and University Hospitals, 11100 Euclid Avenue, Cleveland, OH, 44114, USA. Musaddiq.Awan@UHHospitals.org.
authors.forename: Musaddiq J
authors.initials: MJ
authors.lastname: Awan
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, University Hospitals, Cleveland, OH, USA.
authors.forename: Pierre
authors.initials: P
authors.lastname: Lavertu
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, University Hospitals, Cleveland, OH, USA.
authors.forename: Chad
authors.initials: C
authors.lastname: Zender
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, University Hospitals, Cleveland, OH, USA.
authors.forename: Rod
authors.initials: R
authors.lastname: Rezaee
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, University Hospitals, Cleveland, OH, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Fowler
authors.affiliation: Department of Medical Oncology, University Hospitals, Cleveland, OH, USA.
authors.forename: Lilit
authors.initials: L
authors.lastname: Karapetyan
authors.affiliation: Department of Medical Oncology, University Hospitals, Cleveland, OH, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Gibson
authors.affiliation: Department of Pathology, University Hospitals, Cleveland, OH, USA.
authors.forename: Jay
authors.initials: J
authors.lastname: Wasman
authors.affiliation: Department of Nuclear Medicine and Radiology, University Hospitals, Cleveland, OH, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Faulhaber
authors.affiliation: Department of Radiation Oncology, Case Western Reserve University and University Hospitals, 11100 Euclid Avenue, Cleveland, OH, 44114, USA.
authors.forename: Mitchell
authors.initials: M
authors.lastname: Machtay
authors.affiliation: Department of Radiation Oncology, Case Western Reserve University and University Hospitals, 11100 Euclid Avenue, Cleveland, OH, 44114, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Yao
mesh_terms: D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000532:radiotherapy*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism*; D005260:Female; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: C000614131:CDKN2A protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16
keywords: Head and neck cancer; Human papillomavirus; Neck dissection; PET/CT; Prognostic factors