title: Pairwise comparison of 18F-FDG and 18F-FCH PET/CT in prostate cancer patients with rising PSA and known or suspected second malignancy.
abstract: OBJECTIVE
  This study aimed to evaluate the usefulness of combining fluorine-18 choline (F-FCH) and fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) in patients with rising prostate-specific antigen and known or suspected second malignancy.
  
  
  METHODS
  F-FCH and F-FDG PET/CT were performed 15±9 days apart on the same PET/CT system and acquisition and reconstruction parameters. A mean standardized uptake value (SUVmean) was computed for every lesion that could be discriminated with both tracers. PET results were confirmed by histology (eight patients) and clinical and imaging follow-up (mean±SD: 15±9 months).
  
  
  RESULTS
  Of 77 consecutive patients who underwent F-FCH PET/CT scans for suspected prostate cancer recurrence, 10 (13%) were suspected to have a second malignancy because of F-FCH PET pattern inconsistency with that of prostate cancer (n=6), because of a history of a second malignancy with similar metastatic patterns (n=2) or inconsistency between disease burden and prostate-specific antigen value (n=2). Seventy lesions were studied, with a final diagnosis of prostate cancer, other cancers and benign disease in 55, nine and six lesions, respectively. F-FCH SUVmean and F-FCH/F-FDG SUVmean ratios were significantly different between prostate cancer, nonprostate cancer and benign disease (P<0.0001 and P=0.04, respectively). Receiving operating characteristic analysis showed that the F-FCH/F-FDG ratios were not better than F-FCH SUVmean in discriminating prostate cancer from nonprostate cancer and benign diseases (sensitivity, specificity and area under the curve were 69%, 80%, 0.71 and 84%, 80% and 0.89, respectively).
  
  
  CONCLUSIONS
  We found that F-FCH/F-FDG SUVmean ratios cannot differentiate prostate cancer recurrences from other cancer types when both diagnoses are suspected. Doubtful lesions should be biopsied.
authors.affiliation: aNuclear Medicine Department bBiostatistics and Clinical Research Unit Departments of cMedical Oncology dRadiation Oncology eUro-Oncology Multidisciplinary Staff Meeting, François Baclesse Cancer Centre fNormandie University gNuclear Medicine Department, University Hospital, Caen, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: How Kit
authors.forename: Audrey E
authors.initials: AE
authors.lastname: Dugué
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Sevin
authors.forename: Nedjla
authors.initials: N
authors.lastname: Allouache
authors.forename: François
authors.initials: F
authors.lastname: Lesaunier
authors.forename: Florence
authors.initials: F
authors.lastname: Joly
authors.forename: Nicolas
authors.initials: N
authors.lastname: Aide
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001692:Biological Transport; D002794:Choline / Q000031:analogs & derivatives* / Q000378:metabolism; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D008297:Male; D016609:Neoplasms, Second Primary / Q000000981:diagnostic imaging* / Q000473:pathology; D000072078:Positron Emission Tomography Computed Tomography; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology
chemical_list: D019788:Fluorodeoxyglucose F18; C514960:fluorocholine; D017430:Prostate-Specific Antigen; D002794:Choline