title: Assessment of outcomes with delayed (18)F-FDG PET-CT response assessment in head and neck squamous cell carcinoma.
abstract: OBJECTIVE
  To assess the accuracy of a 4-month post-(chemo)radiotherapy 18-fludeoxyglucose ((18)F-FDG) positron emission tomography (PET)-CT for head and neck squamous cell carcinoma (HNSCC).
  
  
  METHODS
  105 patients who underwent a baseline and response assessment (18)F-FDG PET-CT scan between 2008 and April 2013 were identified. (18)F-FDG PET-CT outcomes were analysed with reference to clinicopathological outcomes.
  
  
  RESULTS
  79 of 105 (75%) (18)F-FDG PET-CT scans demonstrated a complete metabolic response; 19 of 101 (19%) for assessable primary tumours were positive; and 19 of 93 (20%) for patients with nodal disease were equivocal (n = 10) or positive (n = 9). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for primary and nodal disease were 90%, 89%, 47%, 99% and 91%, 89%, 53% and 99%, respectively. Eight of nine patients with a positive nodal response scan had clinicopathological evidence of residual nodal disease (PPV, 89%). 2 of 10 patients with equivocal nodal responses had clinicopathological evidence of residual nodal disease (PPV, 20%).
  
  
  CONCLUSIONS
  (18)F-FDG PET-CT 4 months post treatment has a very high NPV. A positive (18)F-FDG PET-CT has a high PPV for residual nodal disease. By contrast, patients who have an equivocal nodal response have a low PPV.
  
  
  CONCLUSIONS
  Response assessment (18)F-FDG PET-CT is a valuable tool in guiding the selective use of neck dissection following (chemo)radiotherapy for HNSCC. An equivocal lymph node response has a limited predictive value for persistent disease, and optimal management remains a clinical challenge.
authors.affiliation: 1 Department of Clinical Oncology, St James's Institute of Oncology, Leeds, UK.
authors.forename: F
authors.initials: F
authors.lastname: Slevin
authors.affiliation: 2 Department of Radiology, St James's Institute of Oncology, Leeds, UK.|3 Department of Nuclear Medicine, St James's Institute of Oncology, Leeds, UK.
authors.forename: M
authors.initials: M
authors.lastname: Subesinghe
authors.affiliation: 1 Department of Clinical Oncology, St James's Institute of Oncology, Leeds, UK.
authors.forename: S
authors.initials: S
authors.lastname: Ramasamy
authors.affiliation: 1 Department of Clinical Oncology, St James's Institute of Oncology, Leeds, UK.
authors.forename: M
authors.initials: M
authors.lastname: Sen
authors.affiliation: 2 Department of Radiology, St James's Institute of Oncology, Leeds, UK.|3 Department of Nuclear Medicine, St James's Institute of Oncology, Leeds, UK.
authors.forename: A F
authors.initials: AF
authors.lastname: Scarsbrook
authors.affiliation: 1 Department of Clinical Oncology, St James's Institute of Oncology, Leeds, UK.
authors.forename: R J D
authors.initials: RJ
authors.lastname: Prestwich
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D016190:Carboplatin / Q000008:administration & dosage; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000188:drug therapy; D059248:Chemoradiotherapy / Q000379:methods; D002945:Cisplatin / Q000008:administration & dosage; D005260:Female; D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D000077195:Squamous Cell Carcinoma of Head and Neck; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D016190:Carboplatin; D002945:Cisplatin