title: 18F-fluorodeoxyglucose positron emission tomography/computed tomography in the assessment of occult primary head and neck cancers--an audit and review of published studies.
abstract: OBJECTIVE
  To assess the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in patients with squamous cell and undifferentiated cancer neck nodes and no primary site on conventional assessment.
  
  
  METHODS
  Seventy-eight patients with neck nodal metastases from an unknown primary cancer were studied. PET/CT was carried out in all patients, 1h after FDG injection.
  
  
  RESULTS
  Uptake suspicious of an occult primary cancer was found in 46/78 (59.0%) patients. Subsequent investigations confirmed a primary site in the base of the tongue in 14, pharyngeal palatine tonsil in 14, post cricoid in one, lung in one. PET/CT diagnosed primary cancers in 30/78 patients (38.5%); sensitivity, specificity, positive predictive value, negative predictive value: 30/30 (100.0%), 32/48 (66.7%), 30/46 (65.2%), 32/32 (100.0%), respectively. PET/CT detected additional disease in four patients: contralateral nodal disease in two, mediastinal nodal disease in one and liver metastases in one.
  
  
  CONCLUSIONS
  FDG PET/CT is of value in the assessment of patients with occult head and neck primary cancers. However, false-positive results remain a limitation of the investigation.
authors.affiliation: Paul Strickland Scanner Centre, Mount Vernon Hospital, Northwood, UK. wailupwong@gmail.com
authors.forename: W L
authors.initials: WL
authors.lastname: Wong
authors.forename: L I
authors.initials: LI
authors.lastname: Sonoda
authors.forename: A
authors.initials: A
authors.lastname: Gharpurhy
authors.forename: F
authors.initials: F
authors.lastname: Gollub
authors.forename: D
authors.initials: D
authors.lastname: Wellsted
authors.forename: K
authors.initials: K
authors.lastname: Goodchild
authors.forename: C
authors.initials: C
authors.lastname: Lemon
authors.forename: R
authors.initials: R
authors.lastname: Farrell
authors.forename: M
authors.initials: M
authors.lastname: Saunders
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011379:Prognosis; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18