Prostate magnetic resonance imaging to predict grade concordance, extra prostatic extension, and biochemical recurrence after radical prostatectomy

Objectives: To investigate whether preoperative prostate MRI findings predicted biopsy to radical prostate (RP) grade group concordance, presence of extraprostatic extension (EPE), and biochemical recurrence (BCR) after RP. Material and methods: We conducted a multi-institutional study (tertiary academic center and community practice) including patients who underwent RP (2014-2021) with preoperative MRI. Grade concordance for systematic, targeted, and combined prostate biopsy was compared to RP. Concordances were also compared for a contemporaneous RP cohort without prebiopsy MRI (No MRI cohort). We assessed association of extracapsular extension on MRI (MRI-ECE) with EPE and BCR after RP. Results: Among 768 men, concordance between biopsy and RP was 65.7% for combined, 58.3% for targeted, and 44.7% for systematic biopsy (P < 0.001). There was no difference in upgrading, concordance, and downgrading compared to 1014 men in the No MRI cohort (P = 0.6). Combined biopsy decreased upgrading to Grade Group ≥3 by 9.2%. EPE after RP was present in 292/768 (38%). MRI-ECE had 56% sensitivity, 74% specificity, 57% positive predictive value, and 73% negative predictive value. MRI-ECE was associated with EPE (OR: 2.25, P < 0.001) and BCR (HR: 1.77, P = 0.006). An MRI-based model improved EPE prediction in the development cohort (AUC 0.80) compared to a traditional nomogram but failed external validation (AUC 0.68). Conclusions: Preoperative MRI findings predicted grade concordance, presence of EPE, and risk of BCR after RP. Variability in MRI-ECE interpretation limited generalizability of models to predict EPE indicating a need for more standardized reporting to increase clinical utility.