title: Utility of quantitative 18 F-fluorodeoxyglucose uptake measurement to identify occult tonsillar carcinoma in patients with cervical metastasis of unknown primary tumours: a retrospective case-control study.
abstract: OBJECTIVE
  Due to relatively high (18) F-fluorodeoxyglucose accumulation in the tonsillar region, the detection of occult tonsillar cancers by (18) F-fluorodeoxyglucose positron emission tomography/computerised tomography remains controversial. Therefore, we assessed the usefulness of quantitative tonsil (18) F-fluorodeoxyglucose uptake in identifying occult tonsillar squamous cell carcinoma.
  
  
  METHODS
  A case-control study of retrospective cohorts.
  
  
  METHODS
  University Teaching Hospital.
  
  
  METHODS
  We assessed all patients diagnosed with tonsillar cancers or cervical lymph node metastasis of unknown primary tumours between 2005 and 2010 who underwent (18) F-fluorodeoxyglucose positron emission tomography/computerised tomography. The subjects were grouped into A (apparent early pT-stage tonsillar squamous cell carcinoma; n = 27), B (occult tonsillar squamous cell carcinoma, primary tumours were found by surgery; n = 21), C (cervical metastasis of unknown primary tumour, primary tumours were not found by surgery and for follow-up; n = 16) and D (33 healthy controls). Tonsillar maximum standardised uptake values were bilaterally measured and compared between groups.
  
  
  RESULTS
  The sensitivity and specificity of qualitative assessment of (18) F-fluorodeoxyglucose positron emission tomography/computerised tomography for detection of occult tonsillar cancers were 67% and 69%, respectively. Mean maximum standardised uptake values of tonsils with cancer were 11.19 ± 5.46 in group A and 8.12 ± 4.52 in group B, which were significantly higher than that of group C (4.62 ± 1.76) or group D (4.57 ± 1.62) (P < 0.01). The mean maximum standardised uptake value differences of groups A (6.35) and B (3.11) were significantly greater than those of groups C (0.32) and D (0.59) (P < 0.01). Similarly, the mean maximum standardised uptake value ratios of groups A (2.47) and B (1.73) were significantly greater than those of groups C (1.06) and D (1.16) (P < 0.01).
  
  
  CONCLUSIONS
  (18) F-fluorodeoxyglucose positron emission tomography/computerised tomography with tonsil SUVmax measurement is useful to identify occult tonsillar squamous cell carcinoma.
authors.affiliation: Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: H J
authors.initials: HJ
authors.lastname: Lee
authors.forename: J S
authors.initials: JS
authors.lastname: Kim
authors.forename: J-L
authors.initials: JL
authors.lastname: Roh
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.forename: K-J
authors.initials: KJ
authors.lastname: Cho
authors.forename: G C
authors.initials: GC
authors.lastname: Park
authors.forename: S-H
authors.initials: SH
authors.lastname: Choi
authors.forename: S Y
authors.initials: SY
authors.lastname: Nam
authors.forename: S Y
authors.initials: SY
authors.lastname: Kim
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009333:Neck; D009367:Neoplasm Staging; D009382:Neoplasms, Unknown Primary / Q000000981:diagnostic imaging* / Q000473:pathology; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed; D014067:Tonsillar Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18