Application of the PRECISION Trial Biopsy Strategy to a Contemporary Magnetic Resonance Imaging-Targeted Biopsy Cohort—How Many Clinically Significant Prostate Cancers are Missed?

To demonstrate the generalizability of PRECISION findings and apply the PRECISION biopsy strategy to a contemporary cohort to characterize cancers missed by employing this strategy.A total of 629 men biopsied between February 2015 and September 2018 met PRECISION inclusion criteria. Men with PI-RADS™ 1-2 magnetic resonance imaging were only biopsied if high clinical suspicion for cancer. Missed cancers were defined as prostate cancer identified uniquely on systematic biopsy in men with PI-RADS 3-5 magnetic resonance imaging, or on either systematic biopsy or magnetic resonance imaging-targeted prostate biopsy in men with PI-RADS 1-2 magnetic resonance imaging. Outcomes included 1) clinically significant prostate cancer, Gleason grade group 2 or greater, detection rate, 2) missed clinically significant prostate cancer rate upon application of PRECISION biopsy strategy, 3) Gleason grade group distribution, core size, spatial orientation and oncologic risk among missed cancers.Application of the PRECISION biopsy strategy to the study cohort resulted in avoidance of biopsy in 28%, similar magnetic resonance imaging-targeted prostate biopsy detection rate to PRECISION, reduction of Gleason grade group 1 detection rate by 60% and reduction of clinically significant prostate cancer detection rate by 19%. Missed clinically significant prostate cancers were often smaller than 6 mm (54.5%), Gleason grade group 2 (67.3%) and low risk by clinical nomogram (74.6%). Gleason grade group 1 cancers identified uniquely on systematic biopsy were often contralateral to magnetic resonance imaging target (46.4%), while missed clinically significant prostate cancer was predominantly ipsilateral (81%). Limitations include biopsy of only men with high risk clinical features among PI-RADS 1-2 magnetic resonance imaging, potentially overestimating the clinically significant prostate cancer detection rate.The study cohort demonstrated generalizability of PRECISION findings. Applying the PRECISION biopsy strategy greatly reduces Gleason grade group 1 detection rate, while missing a small number of clinically significant prostate cancer, typically small volume, low risk, and Gleason grade group 2. Missed clinically significant prostate cancer is predominantly ipsilateral to magnetic resonance imaging target, possibly representing targeting error.