Optimizing MRI-targeted prostate biopsy: the diagnostic benefit of additional targeted biopsy cores.

Introduction: The optimal number of biopsy cores to obtain during MRI-targeted prostate biopsy remains ill-defined. This study sought to determine the optimal number of targeted biopsy cores to obtain from a region of interest to maximize detection of clinically significant prostate cancer.

Materials And Methods: Consecutive patients undergoing MRI-targeted prostate biopsy at a single institution that newly implemented a targeted biopsy pathway from May 2017 to February 2018 were prospectively enrolled. Five biopsy cores were obtained and individually analyzed from each region rated ≥3 on PI-RADS v2.0 to determine the incremental diagnostic benefit of each additional targeted biopsy core. Variables associated with increasing Grade Group from the first to fifth biopsy core were assessed.

Results: One hundred and four patients (79% for elevated PSA) were enrolled, 82% of which had a prior biopsy. Men with a PI-RADS >3 lesion were more likely to have pathologic upgrading with additional targeted biopsy cores (OR:4.76; 95% CI:2.34-9.70; P < 0.0001), particularly to Grade Group ≥2 (OR:5.16; 95% CI:2.17-12.29; P = 0.0002), compared to men with PI-RADS 3 lesions. Detection of clinically significant cancer increased from 26% to 44% to 52% when comparing the first, third, and fifth biopsy cores amongst men with a PI-RADS >3 lesion and from 1% to 4% to 9% for PI-RADS 3 lesions. Urinary retention was the most common complication, occurring in 6 (5.7%) patients.

Conclusion: Clinically significant prostate cancer detection is improved with increased number of MRI-targeted biopsy cores, particularly for urologists early in their learning curve.