Prognostic Implications of Multiparametric Magnetic Resonance Imaging and Concomitant Systematic Biopsy in Predicting Biochemical Recurrence After Radical Prostatectomy in Prostate Cancer Patients Diagnosed with Magnetic Resonance Imaging–targeted Biopsy

Abstract

BackgroundThe prognostic role of multiparametric magnetic resonance imaging (mpMRI) and systematic biopsy in predicting biochemical recurrence (BCR) after radical prostatectomy (RP) in prostate cancer (PCa) patients has not been addressed yet. ObjectiveTo develop a risk tool predicting BCR after RP in patients diagnosed with magnetic resonance imaging (MRI)-targeted biopsy. Design, setting, and participantsA total of 804 patients with a clinical suspicion of PCa and positive mpMRI diagnosed with MRI-targeted plus concomitant systematic biopsy treated with RP were identified. Outcome measurements and statistical analysesThe outcome was represented by BCR defined as two prostate-specific antigen (PSA) values ≥0.2ng/ml after surgery. Multivariable Cox regression analyses assessed the predictors of BCR. A risk tool model based on imaging and biopsy parameters was developed and validated internally. The c-index, calibration plot, and decision curve analyses were used to assess discrimination, calibration, and the net benefit associated with its use in predicting BCR at 36 mo. Results and limitationsMedian (interquartile range) follow-up was 28 (25–29) mo, and 89 patients experienced BCR. The 36-mo BCR-free survival rate was 89%. The maximum diameter of the index lesion and seminal vesicle invasion (SVI) at mpMRI as well as the presence of clinically significant PCa at systematic biopsy (defined as a grade group of >2) were associated with BCR (all p≤0.03). A model based on PSA, Prostate Imaging Reporting and Data System score, SVI at mpMRI, diameter of the index lesion, grade group at MRI-targeted biopsy, and clinically significant PCa at systematic biopsy achieved the highest discrimination (77%) among all clinical models, as well as the European Association of Urology risk groups (62%) and the Cancer of the Prostate Risk Assessment (CAPRA) score (60%). This tool was characterized by excellent calibration at internal validation and the highest net benefit when predicting BCR for the threshold risk between 0% and 30%. ConclusionsThe adoption of predictive models accounting for mpMRI and MRI-targeted biopsy-derived variables and concomitant systematic biopsy would improve clinicians’ ability to identify patients at a higher risk of early recurrence after surgery. Patient summaryThe use of information obtained at multiparametric magnetic resonance imaging (mpMRI), and MRI-targeted and concomitant systematic biopsy would improve clinicians’ ability to identify prostate cancer patients at a higher risk of experiencing early biochemical recurrence after surgery.