The CONFIRM trial protocol: the utility of prostate‐specific membrane antigen positron emission tomography/computed tomography in active surveillance for prostate cancer

Abstract

ObjectivesPrimary objectives: To determine the additive value of prostate‐specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) in the risk stratification of men with newly diagnosed prostate cancer (PCa) who would have otherwise been deemed suitable for active surveillance (AS). Specifically, we aim to determine if PSMA PET/CT can detect a cohort of men on AS that are in fact high risk and likely to experience unfavourable outcomes should they remain on their current treatment pathway. Secondary objectives: to determine the additive value of PSMA PET/CT to repeat multiparametric magnetic resonance imaging (mpMRI) of the prostate and explore whether a confirmatory biopsy may be avoided in men with a negative PSMA PET/CT and a negative repeat mpMRI of the prostate (Prostate Imaging‐Reporting and Data System score of <3). Furthermore, to develop a nomogram combining clinical, imaging and biomarker data to predict the likelihood of failure on AS in men with high‐risk features. Also, a blood sample will be taken to perform a Prostate Health Index test at the time of confirmatory biopsy. Furthermore, a portion of this blood will be stored at a biobank for up to 5 years if a follow‐up study on molecular biomarkers and genetic assays in this cohort of men is indicated, based on the results from the CONFIRM trial.Patients and MethodsThe CONFIRM trial is a prospective, multicentre, pre‐test/post‐test, cohort study across Victoria, Australia, involving men with newly diagnosed low‐risk PCa with high‐risk features, considered suitable for AS and undergoing confirmatory biopsy. The trial's goal is to provide high‐quality evidence to establish whether PSMA PET/CT has a role in risk‐stratifying men deemed suitable for AS despite having high‐risk feature(s).ResultsThe CONFIRM trial will measure the proportion of men deemed unsuitable for ongoing AS based on pathological upgrading and multidisciplinary team recommendation due to PSMA PET/CT scan and PSMA‐targeted confirmatory biopsy. Additionally, the positive and negative predictive values, sensitivity, and specificity of PSMA PET/CT will be calculated in isolation and combined with repeat mpMRI of the prostate.ConclusionsThis trial will provide robust prospective data to determine if PSMA‐PET/CT and standard of care (prostate biopsy ± repeat mpMRI) can improve diagnostic certainty in men undergoing confirmatory biopsy for low‐grade PCa with high‐risk features.