Introduction: To determine the impact of prebiopsy prostate magnetic resonance imaging (MRI) followed by a targeted biopsy (TBx) approach for initial diagnosis on oncological outcomes after prostate cancer (PCa) treatment. Methods: We performed a retrospective review of all patients who underwent prostate biopsy followed by radiation therapy (RT) or radical prostatectomy (RP) as their first treatment at our center from 2014-2020. Patients were separated into two cohorts based on the diagnostic approach: prebiopsy prostate MRI during initial evaluation and those who did not receive MRI. Patients with positive MRI findings underwent a combination of TBx and systematic biopsy (SBx) to confirm diagnosis while those without MRI underwent SBx only. Patients with prostate specific antigen (PSA) >20 were excluded. Kaplan-Meier curve analysis was used to compare biochemical recurrence (BCR, defined as PSA > 0.2ng/ml after RP or a rise of 2ng/ml after RT) between cohorts. Cox proportional hazard analysis was done to determine the predictors of the BCR. Results: 366 patients (174 diagnosed by SBx only, and 192 diagnosed by prebiopsy MRI and TBx) with a median follow-up of 40 months were included in the study. 245 men (67%) had RP as their first treatment. Median age and PSA were 64.7 and 7.9 respectively in the SBx cohort and 65.0 and 8.3 respectively in TBx cohort. There was a significant difference in BCR rate between the TBx (7.98%) versus SBx (19.28%, p<0.05 by log rank). After adjusting for age, race, PSA, biopsy path, DRE, and family history, prebiopy MRI and TBx approach for diagnosis was found to be an independent negative predictor (p=0.001); with patients diagnosed with the above approach 71% less likely to have BCR during the study period. Conclusions: Our study shows that patients undergoing prebiopsy MRI followed by TBx have lower rates of BCR compared to men diagnosed without prebiopsy MRI. To our knowledge, this study is the first to show the positive impact of prebiopsy MRI on oncological outcomes, likely due to its role in risk stratification, treatment selection and surgical staging and planning. Further longitudinal studies are needed to discern the true long-term benefits of prebiopsy MRI on oncological outcomes. SOURCE OF Funding: None.
