(UroToday.com) PSMA PET/CT scans are being increasingly utilized in the staging evaluation of prostate cancer, quickly replacing traditional imaging, especially for high risk disease. However, there is limited data regarding the utility of the standardized uptake value (SUVmax) of the primary prostate lesion in the PSMA PET scan. Usually, we are focused more on extraprostatic disease. Therefore, they evaluated whether the SUVmax of the primary prostate lesion can indicate aggressive pathological features in patients undergoing radical prostatectomy (RP) with an extended pelvic nodal dissection (PLND).
They retrospectively reviewed a prospectively maintained institutional database for prostate cancer patients who underwent RP with PLND between 2015-2022 and who had a PSMA PET scan for their staging evaluation. The SUVmax of the primary lesion in the prostate was noted & compared across the pathological Gleason grade groups (GGG). They also checked whether the SUVmax was associated with Gleason Grade upgrading & pathological nodal status.
A total of 205 patients were included & were stratified into the following clinical risk groups based on MRI & PSMA-PET scans: 6 (2.9%) low-risk, 49 (23.9%) intermediate-risk, 46 (22.4%) high-risk localized, 89 (43.4%) locally-advanced node-negative & 15 (7.3%) node-positive patients.
The median SUVmax of the primary prostate lesion for pathological GGG 1, 2, 3, 4 & 5 were 6.45, 11.3, 18.11, 25.51 & 24.37 respectively (p<0.001).
For the 153 patients with a Gleason Grade Group 1-3 on transrectal biopsy, 19 patients had an upgrading of their GGG >= 4 on the final pathology. The median SUV max of the prostate lesion in these 19 patients was significantly higher [median 22.37 (IQR 15.5 – 33.1)] than that in the remaining 134 patients with biopsy GG1-3 disease who did not have an upgrading [median 11.3 (IQR 7.4 – 17.5)]; p<0.001 (Fig 1).
Using a cutoff of 15, their AUC was 0.792 at predicting upgrading. Much higher than nomograms. The median SUVmax of the primary prostate lesion in patients who were true negatives for nodes, as per the PSMA-PET scan & final pathology, was significantly lower (12.8 vs 26.4, p<0.001) than that in patients who were false negative (cN0 on PSMA but pN+ in final pathology).
Based on this, the authors note that a higher SUVmax of the primary prostate lesion is a potentially important indicator of aggressive pathological behavior - specifically Gleason Grade Group upgrading and PLND positive disease. Larger data is required to determine reliable SUVmax cutoff.Presented by: Gagan Prakash, MD, Tata Memorial Centre, Mumbai, India
Written by: Thenappan (Thenu) Chandrasekar, MD – Urologic Oncologist, Associate Professor of Urology, University of California, Davis @tchandra_uromd @UCDavisUrology on Twitter during the 2023 American Urological Association (AUA) Annual Meeting, Chicago, IL, April 27 – May 1, 2023