Does 1.5 T mpMRI play a definite role in detection of clinically significant prostate cancer? Findings from a prospective study comparing blind 24-core saturation and targeted biopsies with a novel data remodeling model.

BACKGROUND: Multiparametric-magnetic resonance imaging (mpMRI) can accurately detect high-grade and larger prostate cancers (PC). AIMS: To evaluate the ability of 1.5 T magnetic field mpMRI-targeted Prostate Biopsies (PBx) in predicting PC in comparison with blind 24-core saturation PBx (sPBx). METHODS: We prospectively collected data from patients undergoing transrectal sPBx and, if needed, targeted PBx of suspected lesions based on the 16-'region-of-interest' (ROI) PI-RADS graph. Data remodeling: for each 'target' (each suspected lesion at mpMRI), we identified all the 16 'ROIs' into which the lesion extended: these single 'ROIs' were identified as 'macro-targets'. For each 'ROI' and 'macro-target', we compared the mpMRI result with that of a saturation and targeted biopsy (if performed). RESULTS: 1.5T mpMRI showed a PI-RADS value ≥ 3 in 101 patients (82.1%). We found a PC in 50 (40.6%). Negative-positive predictive values for mpMRI were 82-45%, respectively. Of the 22 patients with normal mpMRI, four had a PC, but none had a clinically significant cancer. After the data remodeling, we demonstrated the presence of PC in 228 'ROIs': (a) only in targeted biopsies in 15 'ROIs'/'macro-targets' (6.6%); (b) only in sPBx in 177 'ROIs' (77.6%); (c) in both targeted and sPBx in 36 'ROIs' (15.8%). DISCUSSION: 81.8% of patients with normal 1.5T mpMRI were negative at PBx. Performing only targeted PBx may lead to lack of PC diagnosis in about 50% of patients. CONCLUSIONS: In patients with suspected PC and a previous negative PBx, a normal mpMRI may exclude a clinically significant PC, avoiding sPBx.