How Many Cores Should Be Collected per Region of Interest in Fusion Targeted Prostate Biopsy? A Retrospective Single Institution Statistical Simulation.

Objective: To determine how many cores should be collected per region of interest (ROI) in magnetic resonance imaging-guided fusion prostate biopsy. Magnetic resonance imaging-guided targeted prostate biopsy has led to improved detection of clinically significant prostate cancer (csPC); however, data is limited regarding the optimal number of biopsy cores that should be taken. An ideal number of cores maximizes clinically significant cancer detection while minimizing cost, discomfort, and procedure time.

Methods: Patients receiving targeted prostate biopsy (4 cores per ROI) combined with systematic 12-core prostate at our institution between January 2017 and June 2022 were retrospectively identified. Statistical simulation was used to model scenarios in which 1, 2, 3, or 4 cores were taken from the ROI, and the rate of grade group ≥2 prostate cancer (csPC) detection was determined for targeted and combined targeted plus systematic biopsy.

Results: 483 patients were identified. Transrectal (96%) and transperineal (4%) biopsies were included. For targeted biopsy, csPC was present in 21% (1 core), 26% (2 cores; P = .048), 29% (3 cores; P = .002), and 31% (4 cores; P < .001) of cases. For combined biopsy, csPC was present in 33% (1 core), 35% (2 cores; P = .4), 37% (3 cores; P = .2), and 38% (4 cores; P = .12) of cases.

Conclusion: If targeted biopsy is performed without systematic biopsy, 2 or more cores is superior to 1 core for detecting csPC. This effect is mitigated when targeted and systematic biopsy are combined.