title: Role for (11)C-choline PET in active surveillance of prostate cancer.
abstract: BACKGROUND
  Active surveillance (AS) is an increasingly popular management strategy for men diagnosed with low-risk indolent prostate cancer. Current tests (prostate-specific antigen [PSA], clinical staging, and prostate biopsies) to monitor indolent disease lack accuracy. (11)C-choline positron emission tomography (PET) has excellent detection rates in local and distant recurrence of prostate cancer. We examine (11)C-choline PET for identifying aggressive prostate cancer warranting treatment in the AS setting.
  
  
  METHODS
  In total, 24 patients on AS had clinical assessment and PSA testing every 6 months and (11)C-choline PET and prostate biopsies annually. The sensitivity and specificity to identify prostate cancer and progressive disease (PD) were calculated for each (11)C-choline PET scan.
  
  
  RESULTS
  In total, 62 biopsy-paired, serial (11)C-choline PET scans were analyzed using a series of standard uptake value-maximum (SUVmax) cut-off thresholds. During follow-up (mean 25.3 months), 11 of the 24 low-risk prostate cancer patients developed PD and received definitive treatment. The prostate cancer detection rate with (11)C-choline PET had moderate sensitivity (72.1%), but low specificity (45.0%). PD prediction from baseline (11)C-choline PET had satisfactory sensitivity (81.8%), but low specificity (38.5%). The addition of clinical parameters to the baseline (11)C-choline PET improved specificity (69.2%), with a slight reduction in sensitivity (72.7%) for PD prediction.
  
  
  CONCLUSIONS
  Addition of (11)C-choline PET imaging during AS may help to identify aggressive disease earlier than traditional methods. However, (11)C-choline PET alone has low specificity due to overlap of SUV values with benign pathologies. Triaging low-risk prostate cancer patients into AS versus therapy will require further optimization of PET protocols or consideration of alternative strategies (i.e., magnetic resonance imaging, biomarkers).
authors.affiliation: Division of Radiation Oncology, Department of Oncology, University of Alberta, Edmonton, AB;
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Boychak
authors.affiliation: Department of Oncology, University of Alberta, Edmonton, AB;
authors.forename: Larissa
authors.initials: L
authors.lastname: Vos
authors.affiliation: Division of Nuclear Medicine, Department of Oncology, University of Alberta, Edmonton, AB.
authors.forename: William
authors.initials: W
authors.lastname: Makis
authors.affiliation: Division of Nuclear Medicine, Department of Oncology, University of Alberta, Edmonton, AB.
authors.forename: Francois-Alexandre
authors.initials: FA
authors.lastname: Buteau
authors.affiliation: Division of Radiation Oncology, Department of Oncology, University of Alberta, Edmonton, AB;
authors.forename: Nadeem
authors.initials: N
authors.lastname: Pervez
authors.affiliation: Division of Radiation Oncology, Department of Oncology, University of Alberta, Edmonton, AB;
authors.forename: Matthew
authors.initials: M
authors.lastname: Parliament
authors.affiliation: Division of Nuclear Medicine, Department of Oncology, University of Alberta, Edmonton, AB.
authors.forename: Alexander J B
authors.initials: AJ
authors.lastname: McEwan
authors.affiliation: Division of Radiation Oncology, Department of Oncology, University of Alberta, Edmonton, AB;
authors.forename: Nawaid
authors.initials: N
authors.lastname: Usmani
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