Magnetic Resonance Imaging-led Risk-adapted Active Surveillance for Prostate Cancer: Updated Results from a Large Cohort Study

Abstract

Background and objective: Magnetic resonance imaging (MRI)-led active surveillance (AS) for prostate cancer uses prostate-specific antigen (PSA) and MRI for regular monitoring with biopsy only when indicated by changes in MRI or PSA density.

Methods: This clinical cohort, which started AS between February 2000 and July 2023, includes those with (1) Gleason score (GS) ≤3 + 4, (2) PSA <20 ng/ml, and (3) at least two MRI scans. The primary outcome was event-free survival (EFS) defined as histological upgrade to GS ≥4 + 3 or transition to treatment. Patients were risk stratified by baseline MRI visibility and Gleason pattern 4, and Kaplan-Meier curves were used to compare groups.

Key findings and limitations: The cohort consisted of 1150 patients with a median follow-up of 64 mo per person overall (quartiles: 32, 107). At baseline, of these 1150 patients, 412 (36%) had GS 3 + 4, 627 (55%) had an MRI-visible lesion, and 201 (17%) had MRI-visible Gleason 3 + 4 disease. The EFS rate at 5 yr was 91% (95% confidence interval: 88-94%) for nonvisible GS 3 + 3, 71% (65-78%) for MRI-visible GS 3 + 3, 70% (63-78%) for nonvisible GS 3 + 4, and 44% (35-54%) for MRI-visible GS 3 + 4. A total of 487 patients had follow-up biopsies, with 74 having more than one, and histological upgrade to GS ≥4 + 3 was uncommon, occurring in 67 patients. Progression to nodal or bone metastases occurred in ten patients and only in those who had declined the recommended follow-up MRI and/or biopsies. Thirty patients chose treatment despite having stable characteristics, and 31 were lost to follow-up.

Conclusions and clinical implications: MRI visibility and secondary Gleason pattern 4 at baseline are associated with progression to treatment and to primary Gleason pattern 4 during MRI-led AS.

Keywords: Active surveillance; Prostate cancer; Prostate magnetic resonance imaging.