title: Distant metastases and synchronous second primary tumors in patients with newly diagnosed oropharyngeal and hypopharyngeal carcinomas: evaluation of (18)F-FDG PET and extended-field multi-detector row CT.
abstract: BACKGROUND
  Patients with oropharyngeal or hypopharyngeal squamous cell carcinoma (SCC) have a high risk of having distant metastases or second primary tumors. We prospectively evaluate the clinical usefulness of (18)F-fluoro-2-deoxyglucose positron emission tomography ((18)F-FDG PET), extended-field multi-detector computed tomography (MDCT), and their side-by-side visual correlation for the detection of distant malignancies in these two tumors at presentation.
  
  
  METHODS
  A total of 160 patients with SCC of the oropharynx (n = 74) or hypopharynx (n = 86) underwent (18)F-FDG PET and extended-field MDCT to detect distant metastases or second primary tumors. Suspected lesions were investigated by means of biopsy, clinical, or imaging follow-up.
  
  
  RESULTS
  Twenty-six (16.3%) of our 160 patients were found to have distant malignancy. Diagnostic yields of (18)F-FDG PET and MDCT were 12.5% and 8.1%, respectively. The sensitivity of (18)F-FDG PET for detection of distant malignancies was 1.5-fold higher than that of MDCT (76.9% vs. 50.0%, P = 0.039), while its specificity was slightly lower (94.0% vs. 97.8%, P = 0.125). Side-by-side visual correlation of MDCT and (18)F-FDG PET improved the sensitivity and specificity up to 80.8% and 98.5%, respectively, leading to alteration of treatment in 13.1% of patients. A significant difference in survival rates between its positive and negative results was observed.
  
  
  CONCLUSIONS
  (18)F-FDG PET and extended-field MDCT had acceptable diagnostic yields for detection of distant malignancies in untreated oropharyngeal and hypopharyngeal SCC. (18)F-FDG PET was 1.5-fold more sensitive than MDCT, but had more false-positive findings. Their visual correlation improved the diagnostic accuracy, treatment planning, and prognosis prediction.
authors.affiliation: Department of Molecular Imaging Center and Diagnostic Radiology, Chang Gung Memorial Hospital, Linkou Medical Center, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Shu-Hang
authors.initials: SH
authors.lastname: Ng
authors.forename: Sheng-Chieh
authors.initials: SC
authors.lastname: Chan
authors.forename: Chun-Ta
authors.initials: CT
authors.lastname: Liao
authors.forename: Joseph Tung-Chieh
authors.initials: JT
authors.lastname: Chang
authors.forename: Sheung-Fat
authors.initials: SF
authors.lastname: Ko
authors.forename: Hung-Ming
authors.initials: HM
authors.lastname: Wang
authors.forename: Shu-Chyn
authors.initials: SC
authors.lastname: Chin
authors.forename: Chin-Yu
authors.initials: CY
authors.lastname: Lin
authors.forename: Shiang-Fu
authors.initials: SF
authors.lastname: Huang
authors.forename: Tzu-Chen
authors.initials: TC
authors.lastname: Yen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000556:secondary*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016609:Neoplasms, Second Primary / Q000175:diagnosis*; D009959:Oropharyngeal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18