SAN DIEGO, CA USA (UroToday.com) - Once thought to be of little clinical utility in the prostate cancer space, Dr. Annie-Claude Blouin and colleagues from Quebec evaluated the ability of FDG-PET/CT in staging high risk prostate cancer.
Recent literature from in vitro models has shown overexpression of glucose metabolism enzymes in high Gleason sum prostate cancer. Employing the bench-to-bedside paradigm, the authors evaluated FDG-PET/CT in 54 patients with Gleason ≥ 8 prostate cancer and a median PSA of less than 10 prior to local therapy. Increased FDG uptake was found in the various tissues: prostate (44%), lymph nodes (LN 15%), and bone (6%). In those undergoing radical prostatectomy, positive predictive values were 100% for LN metastasis. An overwhelming number of patients had pathologic downgrading to Gleason ≤ 7 when FDG uptake in the prostate was not observed (~70%).
Interestingly, not a single patient who was downstaged to Gleason 6 or 3+4=7 exhibited increased FDG uptake. The authors conclude that that FDG-PET/CT is highly specific for LN metastasis and may also identify patients who will likely be downstaged after radical prostatectomy. Thus, the authors may have identified a novel use for FDG-PET/CT in evaluating high-risk prostate cancer patients prior to primary therapy.
At the session, the moderator, John Davis, MD from MD Anderson Cancer Center, was particularly excited about the possibility of a technology, already widely available to clinicians, to more accurately, clinically stage prostate cancer. One question posed was whether this technology could be applicable for patients undergoing active surveillance to rule out occult high-grade disease within the prostate. The authors responded that such use of FDG-PET will certainly need to be evaluated going forward.
Abstract Title: Determination of the accuracy of FDG-PET/CT in the primary staging of biological high risk prostate cancers before local therapies: increased uptake associated with highly aggressive tumors
Presented by Annie-Claude Blouin, Goran Rimac, F Bouchard, Claude Lemay, Vincent Fradet, A Caron, Yves Fradet, Louis Lacombe, Thierry Dujardin, Rabi Tigert, Jean- Mathieu Beauregard, and F. Pouliot at the American Urological Association (AUA) Annual Meeting - May 4 - 8, 2013 - San Diego Convention Center - San Diego, California USA