MP57-02: MRI versus Non-MRI Diagnostic Pathways before Radical Prostatectomy: Impact on Nerve-Sparing, Positive Surgical Margins, and Biochemical Recurrence

Hiten D. Patel, Goran Rac*, Yudai Okabe, Gaurav Pahouja, Shalin Desai, Steven M. Shea, Alex Gorbonos, Marcus L. Quek, Robert C. Flanigan, Ari Goldberg, Gopal N. Gupta, Maywood, IL

Introduction: Multiparametric MRI-TRUS fusion-guided biopsy has improved detection of clinically significant prostate cancer (csPCa). However, the impact of MRI on surgical outcomes is less well established. We compared MRI and non-MRI diagnostic pathways among patients receiving radical prostatectomy (RP) for the performance of bilateral nerve-sparing, positive surgical margin rates, and biochemical recurrence (BCR).

Methods: Men diagnosed with PCa and receiving RP at LUMC (2014-2021) were included. Patients were categorized into MRI or non-MRI diagnostic pathways based on receipt of MRI before prostate biopsy based on clinical suspicion of prostate cancer. Clinical variables included age, race, DRE, PSA, grade group (GG) on biopsy , and surgical and pathologic data. Multivariable logistic regression models evaluated receipt of bilateral nerve-sparing and positive surgical margin rates. Kaplan-Meier curves and Cox proportional hazards regression evaluated BCR.

Results: Of 609 patients, 281 (46.1%) were in the MRI and 328 (53.9%) in the non-MRI groups. MRI patients had lower rates of positive DRE (10.3% vs. 20.7%, p<0.001) but similar PSA (median 6.9 vs. 6.1, p=0.60) and biopsy GG distribution (GG=3: 39.9% vs. 36.0%) compared to non-MRI patients. Pathologic findings were comparable for RP GG (GG=3: 28.5% vs. 28.4%), pT stage (=pT3a: 54.1% vs. 57.3%), and prostate cancer volume (median 15% vs. 15%, p=0.20). Positive surgical margin rates were slightly lower but not significantly different for the MRI and non-MRI groups (22.8% vs. 26.8%, p=0.25) including on multivariable analysis (OR 0.80 (95%CI 0.56-1.17), p=0.25). Bilateral nerve-sparing rates were higher for the MRI vs. non-MRI groups (69.3% vs. 60.1%, p=0.04) including on multivariable analysis (OR 1.95 (95%CI 1.32-2.88), p=0.001). The MRI group demonstrated improved BCR (HR 0.63 (95%CI 0.40-0.99), p=0.04) after adjustment for age, PSA, RP GG, pT stage, and positive surgical margin status.

Conclusions: A multiparametric MRI-based diagnostic approach was associated with similar positive surgical margin rates but greater utilization of bilateral nerve-sparing at RP compared to a non-MRI approach. Cancer control based on BCR favored the MRI group even after adjustment for known prognostic factors.

Source of Funding: Efforts to support data extraction and maintenance of The Prospective Loyola University mpMRI Prostate Biopsy Cohort database is supported by funding from Siemens Medical Solutions USA, Inc.