The Role of Multiparametric Magnetic Resonance Imaging/Ultrasound Fusion Biopsy in Active Surveillance

Background Multiparametric magnetic resonance imaging (mpMRI)/ultrasound fusion biopsy (targeted biopsy or TB) may improve detection of high-grade cancers when compared to systematic biopsy (SB). Objective To assess TB in active surveillance (AS). Design, setting, and participants We retrospectively evaluated SB (12-core sector) and TB among 103 AS men undergoing surveillance biopsy, 54 men undergoing confirmatory biopsy (CB), and 73 men referred for diagnostic biopsy (DB; comparison group). Regions of interest (ROIs) on mpMRI were assigned a PI-RADS score and targeted if the score was ≥3. Outcome measurements and statistical analysis Detection of Gleason score (GS) ≥7 by TB and SB was the outcome of interest, except in a multivariable model, for which any cancer was the outcome. Results and limitations GS ≥7was detected by either biopsy method in 25 men (24.3%) in the AS group, 12 men (22.2%) in the CB group, and 55 men (75.3%) in the DB group.GS ≥7 was found in 24.3% by SB + TB versus 20.4% by SB in the AS group (p = 0.13); in 22.2% by SB + TB versus 16.7% by SB in the CB group (p = 0.25); and in 75.3% by SB + TB versus 58.9% by SB in the DB group (p = 0.002). The sensitivity for GS ≥7 detection was lower for TB than for SB (p = 0.006) in the AS cohort (relative sensitivity ratio 0.33, 95% confidence interval 0.16–0.71). Higher PI-RADS score (4 vs 3, odds ratio [OR] 2.00, p = 0.04; 5 vs 3, OR 4.74, p = 0.02), lower MRI-estimated prostate volume (OR 1.20 per 10-cm³ lower volume, p = 0.01), larger ROI (OR 1.04 per mm, p = 0.02), and right-sided ROI (OR 2.27, p = 0.01) were associated with finding cancer on TB. A potential limitation is that not all men who presented for biopsy underwent TB and the urologist was not blinded to MRI results before SB. Conclusions Owing to the low relative sensitivity of mpMRI for detection of GS ≥7 disease, SB still needs to be performed for men on AS. Patient summary This study suggests that image-guided prostate biopsy alone may not be informative for men enrolled in an active surveillance program for prostate cancer.