Senior Consultant University Medical Center Duesseldorf
Introduction: There is evidence that multiparametric magnetic resonance imaging (mpMRI) may avoid repeat prostate biopsies in monitoring of patients during active surveillance (AS) for prostate cancer (PC). To assess the ability of mpMRI to risk stratify men on AS, including ISUP grade group (GG) 1 and 2 PC to reduce guideline-mandated biopsy, and to predict ISUP GG upgrading. Methods: Prospective 2-year single-center outcome of an mpMRI-guided AS protocol (PROMM-AS). 12 months after AS inclusion with MRI/TRUS fusion-guided biopsy, all men underwent mpMRI. In case of stable mpMRI according to PRECISE criteria, re-biopsy was deferred and follow-up mpMRI after 24 months performed. In case of mpMRI progression or at the end of study, follow-up MRI/TRUS fusion-guided biopsy was indicated. Primary endpoint was a reduction of histopathological AS disqualification from previous published 25% to 15%. A sample size of in total 150 men was calculated to achieve 80% power to detect this rate difference. We calculated sensitivity, specificity, positive (PPV) and negative predictive values (NPV) for ISUP GG upgrading on MRI and performed regression analyses. Results: In total, 101 men (60 with GG1 and 41 with GG2 PC) were available for analysis. Histopathological progression occurred in total in 29 men. Thus, the primary endpoint could not be reached and we performed an interim-analysis. In the GG1 subgroup 18 men had progression (30%), whereas 11 men progressed in GG2 subgroup (27%). Sensitivity, specificity, PPV and NPV for PRECISE was 94%, 64%, 81% and 88% in the GG1 subgroup and 91%, 50%, 91% and 50% in GG2 subgroup. On regression analysis, higher PRECISE scores (4-5), initial PI-RADS, PSA, age and prostate volume were significant predictors of histological progression in ISUP GG1 and higher PRECISE score, initial PI-RADS and previous negative biopsy in ISUP GG2 PC. Conclusions: MRI-guided monitoring of men on AS including PRECISE criteria avoids unnecessary follow-up biopsies in 88% of men with ISUP GG1 and sufficiently predicts GG upgrading over a follow-up period of two years in both ISUP GG1 and GG2. SOURCE OF Funding: None.
