(UroToday.com) The 2024 American Urological Association (AUA) annual meeting held in San Antonio, TX was host to the prostate cancer staging session. Dr. Felix Preisser presented the results of a retrospective study of patients with intermediate and high-risk prostate cancer who had a PSMA PET/CT with an available maximum standardized uptake value (SUVmax) inside the prostate prior to radical prostatectomy. The aim of this study was to assess the ability of the SUVmax at PSMA PET/CT to predict adverse pathology at radical prostatectomy (RP).
Dr. Preisser discussed the standardized uptake value (SUV) max, which represents the SUV normalized for body weight for the most-tracer-avid voxel within a region of interest (ROI). It can be easily calculated using the formula:
- SUVmax = Tracer uptake in ROI/(Injected activity/patient weight)
He then mentioned that despite being a useful measurement index, SUVmax is still semi-quantitative. If a PSMA PET/CT is performed in the same patient on two consecutive days, slightly different SUV values can be obtained in the same area.
This study used a database from a high-volume center, comprising patients with intermediate and high-risk prostate cancer who underwent PSMA PET/CT and had available SUVmax values within the prostate prior to RP. They included 544 patients, with 50.7% classified as D’Amico intermediate risk and 49.3% as high-risk prostate cancer. The median SUVmax in the prostate was 9.5, and the median PSA prior to RP was 8.1 ng/ml.
They utilized Kaplan-Meier curves to compare biochemical recurrence (BCR)-free survival after RP, stratified according to SUVmax. With a median follow-up of 24.6 months, the estimated BCR-free survival at 48 months after RP was 72.1% for patients with SUVmax < 9.5 compared to 62.2% for those with SUVmax ≥ 9.5 (p = 0.03).
Additionally, logistic regression modeling was employed to assess the ability of SUVmax to predict non-organ-confined disease or adverse pathology (defined as non-organ-confined and/or Gleason score ≥ 4+3) during RP. In the logistic regression models, they confirmed that SUVmax (continuously coded and stratified as <9.5 vs. ≥ 9.5) represented an independent predictor for non-organ-confined disease (HR 1.74; 95% CI 1.19-2.55, p<0.01) and adverse pathology at RP (HR 2.5; 95% CI 1.49-3.23, p<0.001).
Dr. Preisser's concluding remarks were:
- SUVmax ≥9.5 on PSMA PET/CT was independently associated with adverse pathology and non-organ-confined disease at RP.
- SUVmax threshold correlates with poorer BCR-free survival post-RP,
Presented by: Felix Preisser, MD, at the Department of Urology, Universität Hamburg-Eppendorf
Written by: Julian Chavarriaga, MD – Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @chavarriagaj on Twitter during the 2024 American Urological Association (AUA) Annual Meeting, San Antonio, TX, Fri, May 3 – Mon, May 6, 2024.