Prospective Randomized Trial Comparing Magnetic Resonance Imaging (MRI)-guided In-bore Biopsy to MRI-ultrasound Fusion and Transrectal Ultrasound-guided Prostate Biopsy in Patients with Prior Negative Biopsies

Abstract

BackgroundA significant proportion of prostate cancers (PCas) are missed by conventional transrectal ultrasound-guided biopsy (TRUS-GB). It remains unclear whether the combined approach using targeted magnetic resonance imaging (MRI)-ultrasound fusion–guided biopsy (FUS-GB) and systematic TRUS-GB is superior to targeted MRI-guided in-bore biopsy (IB-GB) for PCa detection. ObjectiveTo compare PCa detection between IB-GB alone and FUS-GB + TRUS-GB in patients with at least one negative TRUS-GB and prostate-specific antigen ≥4 ng/ml. Design, setting, and participantsPatients were prospectively randomized after multiparametric prostate MRI to IB-GB (arm A) or FUS-GB + TRUS-GB (arm B) from November 2011 to July 2014. Outcome measurements and statistical analysisThe study was powered at 80% to demonstrate an overall PCa detection rate of ≥60% in arm B compared to 40% in arm A. Secondary endpoints were the distribution of highest Gleason scores, the rate of detection of significant PCa (Gleason ≥7), the number of biopsy cores to detect one (significant) PCa, the positivity rate for biopsy cores, and tumor involvement per biopsy core. Results and limitationsThe study was halted after interim analysis because the primary endpoint was not met. The trial enrolled 267 patients, of whom 210 were analyzed (106 randomized to arm A and 104 to arm B). PCa detection was 37% in arm A and 39% in arm B (95% confidence interval for difference, –16% to 11%; p=0.7). Detection rates for significant PCa (29% vs 32%; p=0.7) and the highest percentage tumor involvement per biopsy core (48% vs 42%; p=0.4) were similar between the arms. The mean number of cores was 5.6 versus 17 (p<0.001). A limitation is the limited number of patients because of early cessation of accrual. ConclusionsThis trial failed to identify an important improvement in detection rate for the combined biopsy approach over MRI-targeted biopsy alone. A prospective comparison between MRI-targeted biopsy alone and systematic TRUS-GB is justified. Patient summaryOur randomized study showed similar prostate cancer detection rates between targeted prostate biopsy guided by magnetic resonance imaging and the combination of targeted biopsy and systematic transrectal ultrasound-guided prostate biopsy. An important improvement in detection rates using the combined biopsy approach can be excluded.