Jacinta Bonaddio

Background/Objectives: We conducted an exploratory review of patients in our institutions who had undergone a PSMA PET/CT whilst on active surveillance, determining patient characteristics and trends. Methods: A retrospective cohort study of patients who were on active surveillance for low or favourable intermediate-risk prostate cancer and had a PSMA PET/CT done due to the presence of risk factors was performed. Risk factors that were an indication for PSMA PET/CT were: The presence of ISUP GG 2 disease, or ISUP GG1 disease with a PSA > 10 or a PI-RADS score of 4 or 5 on their MRI. Results: We identified 45 patients who underwent PSMA PET/CT whilst on active surveillance. Of these patients, 14 remained on active surveillance at the time of review, whilst 31 had progressed to definitive treatment. There was a significantly different distribution of PRIMARY scores between these two groups, although the average SUVMax was similar. In our practice, we found PSMA PET/CT to be particularly useful when performing confirmatory biopsies on patients who had normal MRI scans or were unable to go for the MRI at the time of diagnosis. Conclusions: PSMA PET/CT shows promise as a tool for active surveillance, particularly in men with risk factors for progressing to active treatment. However, our cohort was too small to draw definitive conclusions, and further research is needed.

Objective: To synthesise data evaluating the diagnostic utility of prostate‐specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) in intermediate‐risk prostate cancer (PCa), as its role in intermediate‐risk PCa remains uncertain. Methods: A systematic search was conducted for studies evaluating PSMA PET/CT in primary staging of newly diagnosed European Association of Urology (EAU)/National Comprehensive Cancer Network (NCCN) intermediate‐risk, or Gleason Score 7 (International Society of Urological Pathology [ISUP] Grade Group [GG] 2–3) PCa. The primary outcome was overall positive scans (lymph nodes or distant metastases). We also secondarily analysed diagnostic accuracy measuring sensitivity, specificity, positive predictive value, and negative predictive value. Results: In total, 16 studies reported positivity rates ranging from 2.2% to 50.0% in intermediate‐risk PCa. A pooled analysis of 13 studies found a PSMA PET/CT positivity rate of 9% (95% confidence interval [CI] 6–11%). In ISUP GG 2 PCa, positivity ranged from 2.2% to 21.4%, compared to 13.6–33.3% in ISUP GG 3 PCa (across two studies). The overall nodal and metastatic sensitivity of PSMA PET/CT was low in intermediate‐risk men, 33% (95% CI 14–60%). Limitations included small sample sizes, retrospective designs, and limited histopathological confirmation. Conclusion: For primary staging in intermediate‐risk PCa PSMA PET/CT showed a low yield. Limited data exist to guide its use in favourable vs unfavourable subgroups. Robust, prospective studies are needed to define its role in clinical decision‐making, further prognostic benefits, and to inform future guidelines.

Active surveillance remains the preferred treatment for men with low-risk prostate cancer and select men with favourable intermediate-risk prostate cancer. It involves the close observation of clinicopathological parameters to assess for disease progression, aiming to delay or avoid definitive treatment and related toxicities for as long as possible, without compromising oncological outcomes. A recent advancement in prostate cancer staging is the PSMA PET scan, which uses a tracer that strongly binds a highly expressed cellular biomarker for prostate cancer. Recent articles have also demonstrated that PSMA PET may be a useful tool for risk-stratifying prostate cancer, with the SUVMax of the scan correlated with higher-grade prostate cancer. This has ignited interest in the potential use of PSMA PET to identify men with higher-risk prostate cancer who may be unsuitable for active surveillance, particularly those who were incorrectly classified as lower risk upon initial diagnosis. This review article aims to assess the current state of the literature and clinical guidelines regarding the use of PSMA PET as a tool to risk-stratify prostate cancer, and whether it can be incorporated into active surveillance protocols to identify men who were incorrectly risk-stratified at time of initial diagnosis.