title: PET/CT with (18)F-choline after radical prostatectomy in patients with PSA ≤2 ng/ml. Can PSA velocity and PSA doubling time help in patient selection?
abstract: OBJECTIVE
  To investigate the performance of (18)F-fluorocholine ((18)F-FCH) PET/CT in relation to the prostate-specific antigen (PSA) kinetic indexes, PSA doubling time (PSAdt) and PSA velocity (PSAve), in detecting recurrent prostate cancer (PC) in a selected population of patients treated with radical prostatectomy and with PSA ≤2 ng/ml.
  
  
  METHODS
  The study group comprised 79 patients (mean age 70 ± 7 years, range 58 - 77 years) who had been treated with radical surgery 30 to 90 months previously and with biochemical failure (defined as a measurable serum PSA level) who were evaluated with (18)F-FCH PET/CT. In order to establish the optimal threshold for PSAdt and PSAve, the diagnostic performance of PSA, PSAdt and PSAve were compared by receiver operating characteristic analysis.
  
  
  RESULTS
  In the population examined, PSA (mean ± SD) was 1.37 ± 0.44 ng/ml (range 0.21 - 2 ng/ml) before PET/CT examination, PSAdt was 10.04 ± 16.67 months and PSAve was 2.75 ± 3.11 ng/ml per year. (18)F-FCH PET/CT was positive in 44 patients (55 %). PSAve and PSAdt were significantly different between patients with a positive and a negative (18)F-FCH PET/CT scan. Thresholds of 6 months for PSAdt and 1 ng/ml per year for PSAve were selected. For PSAdt ≤6 months the detection rate (DR) was 65 %, and for PSAve >1 ng/ml per year the DR was 67 %. PSA values were not significantly different between patients with a positive and a negative PET/CT scan.
  
  
  CONCLUSIONS
  The results of our study suggest that (18)F-FCH PET/CT could be considered for the evaluation of patients with biochemical recurrence of PC and with low PSA levels. Fast PSA kinetics could be useful in the selection of these patients.
authors.affiliation: Department of Biomedicine and Prevention, University Tor Vergata, viale Oxford 81, 00133, Rome, Italy. agostino.chiaravalloti@gmail.com.
authors.forename: Agostino
authors.initials: A
authors.lastname: Chiaravalloti
authors.affiliation: Department of Biomedicine and Prevention, University Tor Vergata, viale Oxford 81, 00133, Rome, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Di Biagio
authors.affiliation: Department of Biomedicine and Prevention, University Tor Vergata, viale Oxford 81, 00133, Rome, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Tavolozza
authors.affiliation: Neuroimaging Research Unit, Institute of Molecular Bioimaging and Physiology - National research Council, Catanzaro, Italy.
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Calabria
authors.affiliation: Department of Biomedicine and Prevention, University Tor Vergata, viale Oxford 81, 00133, Rome, Italy.|IRCCS Neuromed, Pozzilli, Italy.
authors.forename: Orazio
authors.initials: O
authors.lastname: Schillaci
mesh_terms: D000368:Aged; D002794:Choline / Q000031:analogs & derivatives*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D000072078:Positron Emission Tomography Computed Tomography; D017430:Prostate-Specific Antigen / Q000097:blood / Q000378:metabolism*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000601:surgery*
chemical_list: C514960:fluorocholine; D017430:Prostate-Specific Antigen; D002794:Choline
keywords: PET/CT; PSA; PSA doubling time; PSA kinetics; PSA velocity