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

Abstract

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.