MRI versus non-MRI diagnostic pathways before radical prostatectomy: Impact on nerve-sparing, positive surgical margins, and biochemical recurrence

Purpose: Magnetic resonance imaging (MRI) prior to biopsy has improved detection of clinically significant prostate cancer (CaP), but its impact on surgical outcomes is less well established. We compared MRI vs. non-MRI diagnostic pathways among patients receiving radical prostatectomy (RP) for impact on surgical outcomes.

Materials and methods: Men diagnosed with CaP and receiving RP at Loyola University Medical Center (2014-2021) were categorized into MRI or non-MRI diagnostic pathways based on receipt of MRI before prostate biopsy. Primary outcomes of interest included positive surgical margin (PSM) rates, the performance of bilateral nerve-sparing, and biochemical recurrence (BCR). Multivariable logistic regression models, Kaplan-Meier curves, and Cox proportional hazards regression were employed.

Results: Of 609 patients, 281 (46.1%) were in the MRI and 328 (53.9%) in the non-MRI groups. MRI patients had similar PSA, biopsy grade group (GG) distribution, RP GG, pT stage, and RP CaP volume compared to non-MRI patients. PSM rates were not statistically different for the MRI vs. non-MRI groups (22.8% vs. 26.8%, P = 0.25). Bilateral nerve-sparing rates were higher for the MRI vs. non-MRI groups (OR 1.95 (95%CI 1.32-2.88), P = 0.001). The MRI group demonstrated improved BCR (HR 0.64 (95%CI 0.41-0.99), P = 0.04) after adjustment for age, PSA, RP GG, pT, pN, and PSM status. On meta-analysis, a 5.2% PSM reduction was observed but high heterogeneity for use of nerve-sparing.

Conclusions: An MRI-based diagnostic approach selected patients for RP with a small reduction in PSM rates, greater utilization of bilateral nerve-sparing, and improved cancer control by BCR compared to a non-MRI approach even after adjustment for known prognostic factors.