EAU 2023: PSMA-PET in Local Evaluation of the Prostate for Active Surveillance? No

(UroToday.com) The 2023 European Association of Urology (EAU) annual congress held in Milan, Italy between March 10^th and 13^th, 2023 was host to a plenary session addressing the “right management” of prostate cancer patients in the early detection and active surveillance settings. Professor Roderick van den Bergh was tasked with debating against the need for a PSMA-PET/CT in the local evaluation of the prostate for active surveillance candidates.

Dr. Van den Bergh began by emphasizing that, to date, there is no strong evidence for PSMA-PET/CT usage for the selection of appropriate active surveillance candidates. While Dr. Eapen earlier highlighted results from the PRIMARY trial that demonstrated that a combination approach of mpMRI + ⁶⁸Ga-PSMA/PET-CT for biopsy-naïve patients lowers the percentage of missed clinically significant prostate cancer (csPCa) from 17% to 3%, only 25/162 csPCa lesions were PSMA positive. Of these 25, 15 were Grade Group 2, with 8 GG3, and 2 GG5. As such, the “number needed to scan” was 30 PSMA-PET/CT scans, meaning that 30 additional scans had to be performed to detect one additional case of missed csPCa. Furthermore, addition of PSMA-PET/CT to mpMRI decreases the specificity of the overall findings from 53% to 40%, increasing the false positive rate.¹The PSMA in Active Surveillance for Prostate Cancer Trial (PASPoRT), currently in press, evaluated 145 men on active surveillance. All men underwent a mpMRI with corresponding systematic and targeted biopsies, following which patients had a PSMA-PET/CT scan. 49/145 men underwent additional targeted biopsies with 14 (10%) having disease upgrading (9 GG2, 3 GG3, 1 GG4, and 1 GG5). The number needed to scan in this case was similar to that in PRIMARY (~29).

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There are also many other reasons to avoid PSMA-PET/CT in this cohort of patients:

Cost
Regular active surveillance follow up appears to be sufficient
Impact of increased imaging with PSMA-PET/CT on long-term endpoints remains unknown
Use of PSMA-PET/CT may further contribute to the stage shift previously experienced with mpMRI
Detection of false positive lesions

Dr. van den Bergh also expressed concerns that that routine use of PSMA-PET/CT may artificially “paint” a worse picture for these patients, whereby instead of expanding appropriate active surveillance use for lower risk cohorts, we could artificially upgrade/upstage prostate cancer patients, narrowing the eligibility criteria for active surveillance.

Irrespective of the surveillance modality or intensity chosen, or even the treatment regimen administered, patients with clinically localized prostate cancer have excellent long-term outcomes, as was highlighted this morning by Dr. Freddie Hamdy’s presentation of the 15-year ProtecT outcomes.

active surveillance.jpg

And before we debate the ultimate strategy for active surveillance selection/monitoring, we need to improve on the current active surveillance adoption rates for low-risk patients, which, although improving, remain low in the United States (60% in 2021 from AQUA registry), with significant practice and physician-level variations present.²

Dr. Van den Bergh concluded by highlighting that we need to explore de-escalation strategies, as opposed to further “diagnostic intensification” with the unnecessary use of PSMA-PET/CT in this setting.

Presented by: Professor Roderick van den Bergh, MD, University Medical Center Utrecht, Utrecht, The Netherlands

Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, @zklaassen_md on Twitter during the 2023 European Association of Urology (EAU) Annual Meeting, Milan, IT, Fri, Mar 10 – Mon, Mar 13, 2023.

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