PSMA PET as a Tool for Active Surveillance of Prostate Cancer-Where Are We at?

Abstract

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.

Keywords: PSMA PET; active surveillance; prostate cancer; risk stratification.

Figure 1

Example PSMA PET/CT scans demonstrating intra-prostatic uptake of radiolabelled PSMA tracer. (a) PSMA scan demonstrating low intraprostatic uptake—PRIMARY score of 1; (b) PSMA scan demonstrating a focal area of high tracer uptake—PRIMARY score of 5.