Risk‐stratification based on magnetic resonance imaging and prostate‐specific antigen density may reduce unnecessary follow‐up biopsy procedures in men on active surveillance for low‐risk prostate cancer

Objectives To assess the value of risk‐stratification based on magnetic resonance imaging (MRI) and prostate‐specific antigen density (PSA‐D) in reducing unnecessary biopsies without missing Gleason pattern 4 prostate cancer in men on active surveillance (AS). Patients and Methods In all, 210 men on AS with Gleason score 3 + 3 prostate cancer received a first MRI and if indicated [Prostate Imaging Reporting and Data System (PI‐RADS) score ≥3] targeted biopsy (TBx) using MRI‐transrectal ultrasonography (TRUS) fusion. The MRI was performed 3 months after diagnosis (group A: n = 97), at confirmatory biopsy (group B: n = 39) or at surveillance biopsy after one or more repeat TRUS‐guided systematic biopsies (TRUS‐Bx) (group C: n = 74). The primary outcome was upgrading to Gleason score ≥3 + 4 prostate cancer based on MRI ± TBx in groups A, B and C. Biopsy outcomes were stratified for the overall PI‐RADS score and PSA‐D to identify a subgroup of men in whom a biopsy could have been avoided as no Gleason score upgrading was detected. Results In all, 134/210 (64%) men had a positive MRI and 51/210 (24%) men had Gleason score upgrading based on MRI‐TBx. The percentage of Gleason score upgrading based on MRI‐TBx was 23% (22/97), 23% (9/39) and 27% (20/74) in respectively groups A, B and C. Additional Gleason score upgrading detected by TRUS‐Bx occurred in 8% (3/39) of men in group B and 6% (1/17) of men who received TRUS‐Bx in group C. No Gleason score upgrading was detected by MRI‐TBx in men with a PI‐RADS score of 3 and a PSA‐D of