INTRODUCTION: 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. 11C-choline positron emission tomography (PET) has excellent detection rates in local and distant recurrence of prostate cancer. We examine 11C-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 11C-choline PET and prostate biopsies annually. The sensitivity and specificity to identify prostate cancer and progressive disease (PD) were calculated for each 11C-choline PET scan.
RESULTS: In total, 62 biopsy-paired, serial 11C-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 11C-choline PET had moderate sensitivity (72.1%), but low specificity (45.0%). PD prediction from baseline 11C-choline PET had satisfactory sensitivity (81.8%), but low specificity (38.5%). The addition of clinical parameters to the baseline 11C-choline PET improved specificity (69.2%), with a slight reduction in sensitivity (72.7%) for PD prediction.
CONCLUSIONS: Addition of 11C-choline PET imaging during AS may help to identify aggressive disease earlier than traditional methods. However, 11C-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).
Boychak O, Vos L, Makis W, Buteau FA, Pervez N, Parliament M, McEwan AJ, Usmani N. Are you the author?
Division of Radiation Oncology, Department of Oncology, University of Alberta, Edmonton, AB; Department of Oncology, University of Alberta, Edmonton, AB; Division of Nuclear Medicine, Department of Oncology, University of Alberta, Edmonton, AB.
Reference: Can Urol Assoc J. 2015 Mar-Apr;9(3-4):E98-E103.