A Prospective Comparison of MRI-US Fused Targeted Biopsy Versus Systematic Ultrasound-Guided Biopsy for Detecting Clinically Significant Prostate Cancer in Patients on Active Surveillance

BackgroundIn active surveillance (AS) patients: (i) To compare the ability of a multiparametric MRI (mpMRI)-ultrasound biopsy system to detect clinically significant (CS) prostate cancer with systematic 12-core biopsy (R-TRUSBx), and (ii) To assess the predictive value of mpMRI with biopsy as the reference standard. MethodsSeventy-two men on AS prospectively underwent 3T mpMRI . MRI-ultrasound fusion biopsy (UroNavBx) and R-TRUSBx was performed. CS cancer was defined using two thresholds: 1) GS7 (CS7) and 2) GS=6 with >50% involvement (GS6). CS cancer detection rates and predictive values were determined. ResultsCS7 cancers were found in 19/72 (26%), 7 (37%) identified by UroNavBx alone, 2 (11%) by R-TRUSBx alone (P=0.182). UroNav targeted biopsy was 6.3x more likely to yield a core positive for CS7 cancer compared with R-TRUSBx (25% of 141 versus 4% of 874, P<0.001). Upgrading of GS occurred in 15/72 patients (21%), 13 (87%) detected by UroNavBx and 10 (67%) by R-TRUSBx. The NPV of mpMRI for CS7 cancer was 100%. MRI suspicion level significantly predicted CS cancer on multivariate analysis (OR 3.6, P<0.001). ConclusionUroNavBx detected CS cancer with far fewer cores compared with R-TRUSBx, and mpMRI had a perfect negative predictive value in this population. J. Magn. Reson. Imaging 2015;41:220-225. (c) 2014 Wiley Periodicals, Inc.