Confirmatory MRI and re-biopsy findings during active surveillance in patients with grade group 2 prostate cancer

To report the results of confirmatory MRI/biopsy in a European cohort of MRI-selected patients with Gleason Grade Group (GG) 2 prostate cancer (PCa) in active surveillance (AS).

Multicenter study enrolled patients with GG2 PCa managed by AS between 2016-2024. Serial MRI scans were interpreted according to PRECISE recommendations. Diagnostic accuracy of PRECISE score to predict upgrading on confirmatory biopsy was assessed by calculating sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) with 95% Confident Intervals (CIs).

A total of 77 patients with GG2 PCa was included, with a PI-RADS 4-5 in 48 patients (63%). On confirmatory MRI, 32 cases were classified as PRECISE 4-5 (42%). On confirmatory biopsy, 39 patients (51%) were downgraded to GG0-1, 27 patients (35%) were GG 2 and upgrading occurred in 11 cases (14%). Sensitivity, specificity, NPV and PPV of the PRECISE score 4-5 to detect upgrading was 63.6% (95%CI 31-89), 62.1% (95%CI, 49-74), 91.1% (95%CI, 82-96) and 21.8% (95%CI, 14-32), respectively. In multivariable Cox hazards regression analysis, downgrading at confirmatory biopsy was significantly associated with a reduced risk of subsequent GG3 reclassification (HR 0.125, 95%CI, 0.277-0.560, p = 0.002) and definitive treatment (HR 0.409, 95%CI, 0.199-0.839, p = 0.015).

MRI selection of patients with GG2 PCa in AS allows better initial characterization of the disease. The absence of progression on MRI indicates a very low risk of grade reclassification, but signs of imaging progression are not always predictive of progression and should not be considered alone for prompting active treatment.