title: F-18-fluoro-deoxy-glucose positron-emission tomography scanning in detection of local recurrence after radiotherapy for laryngeal/ pharyngeal cancer.
abstract: BACKGROUND
  The objective of this investigation was to determine whether F18-fluoro-deoxy-glucose (FDG) positron-emission tomography (PET) could differentiate between local recurrence and late radiation effects after radiotherapy for laryngeal/pharyngeal cancer.
  
  
  METHODS
  In a prospective study of 75 patients (67 larynx, eight oro/hypopharynx), 160 laryngoscopies and 109 FDG PET scans were performed on the head and neck region. The mean follow-up time after the first FDG PET scan was 23 months (minimum 1 year).
  
  
  RESULTS
  Local recurrence was diagnosed in 37 patients: 19 after the first biopsy and 18 after follow-up biopsies. For all of the negative initial FDG scans (27), the biopsies that were taken at the same time were negative and no recurrence was seen for at least 1 year. The first FDG scan was a true positive in 34 of 48 patients. In 12 of the 14 patients with false-positive results, FDG scans were repeated; a decreased FDG uptake was found in 9 of the 12. The sensitivity and specificity of the first scan were respectively 92% and 63%; including subsequent FDG scans, the rates were 97% and 82%, respectively.
  
  
  CONCLUSIONS
  When a local recurrence is suspected after radiotherapy for cancer of the larynx/pharynx, an FDG PET scan should be the first diagnostic step. No biopsy is needed if the scan is negative. If the scan is positive and the biopsy negative, a decreased FDG uptake measured in a follow-up scan indicates that a local recurrence is unlikely.
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
authors.forename: C H
authors.initials: CH
authors.lastname: Terhaard
authors.forename: V
authors.initials: V
authors.lastname: Bongers
authors.forename: P P
authors.initials: PP
authors.lastname: van Rijk
authors.forename: G J
authors.initials: GJ
authors.lastname: Hordijk
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007822:Laryngeal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D007828:Laryngoscopy; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology; D010610:Pharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18