Gallium-68 Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography in Active Surveillance for Prostate Cancer Trial (PASPoRT) - Beyond the Abstract

Active surveillance (AS) is the recommended strategy for the treatment of low-risk and selected intermediate-risk prostate cancer. The use of clinical parameters, including prebiopsy magnetic resonance imaging (MRI), to decide between active surveillance (AS) and active therapy for prostate cancer (PCa) leads to imperfect selection. The goal of this prospective study was to determine if the use of PSMA PET/CT combined with additional targeted biopsy could lead to improved patient risk stratification and selection in patients with prostate cancer who recently started active surveillance.

This single-centre prospective cohort study enrolled patients recently diagnosed with PCa who began AS. At diagnosis, all participants had undergone prebiopsy MRI and targeted biopsy for visualised lesions. Patients underwent an additional 68Ga-PSMA PET/CT and targeted biopsy of all PSMA lesions with a maximum standardised uptake value (SUVmax) of ≥ 4 not covered by previous biopsies.

This study found that additional PSMA targeted biopsies were performed in 45 (32%) patients, and in 13 of these patients (9%), ISUP Grade Group upgrading was observed. This led to a number needed to scan (NNS) of 11 for detecting one patient with an upgrade. Of the patients with upgrading, six remained under AS, and seven underwent radical curative treatment: two received radiotherapy and five underwent robot-assisted radical prostatectomy. The univariate logistic regression analysis results suggest that PSMA PET/CT and additional targeted biopsy were especially beneficial for patients with negative MRI findings. Among those patients who underwent additional PSMA targeted biopsy, the univariate logistic regression suggested that upgrading was more commonly seen in patients with higher prostate-specific antigen (PSA) density and negative MRI.

There are several limitations to this study. First, there was no central review of MRI scans, which could result in missed lesions. Second, the upgrading could be due to the correction of previous biopsy errors. Also, upgrading was only a surrogate outcome because a prostatectomy specimen was not available for all patients. Lastly, the sample size of the study was small, making it challenging to identify subgroups of patients where upgrading was most frequent after PSMA PET/CT.

In conclusion, our study provides evidence that PSMA PET/CT has a role in the risk stratification of patient selection for AS.

Written by: Joris G. Heetman,1 Jules Lavalaye,2 Pepijn D. Polm,3 Timo F. W. Soeterik,3 Lieke Wever,3 Leonor J. Paulino Pereira,3 Erik J. R. J. van der Hoeven,4 Harm H. E. van Melick,3 Roderick C. N. van den Bergh3

  1. Department of Urology, Sint Antonius Hospital, Utrecht-Nieuwegein, The Netherlands.
  2. Department of Nuclear Medicine, Sint Antonius Hospital, Utrecht-Nieuwegein, The Netherlands.
  3. Department of Urology, Sint Antonius Hospital, Utrecht-Nieuwegein, The Netherlands.
  4. Department of Radiology, Sint Antonius Hospital, Utrecht-Nieuwegein, The Netherlands.

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