Application of the PRECISION Trial Biopsy Strategy to a Contemporary MRI-Targeted Biopsy Cohort: How Many Clinically Significant Prostate Cancers are Missed?

Abstract

PURPOSE: 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. MATERIALS AND METHODS: 629 men biopsied between 2/2015-9/2018 met PRECISION inclusion criteria. Men with PI-RADS 1-2 MRI were only biopsied if high clinical suspicion for cancer. Missed cancers were defined as prostate cancer (PCa) identified uniquely on systematic biopsy (SB) in men with PI-RADS 3-5 MRI, or on either SB or MRI-targeted prostate biopsy (MRI-TB) in men with PI-RADS 1-2 MRI. Outcomes included 1) clinically-significant PCa (csPCa), ≥Gleason grade group (GG) 2, detection rate (CDR), 2) missed csPCa rate upon application of PRECISION biopsy strategy, 3) GG distribution, core size, spatial orientation, and oncologic risk among missed cancers. RESULTS: Application of the PRECISION biopsy strategy to the study cohort resulted in avoidance of biopsy in 28%, similar MRI-TB CDR to PRECISION, reduction of GG1 CDR by 60%, and reduction of csPCa CDR by 19%. Missed csPCa were often <6 mm (54.5%), GG2 (67.3%), and low-risk by clinical nomogram (74.6%). GG1 cancers identified uniquely on SB were often contralateral to MRI target (46.4%), while missed csPCa was predominantly ipsilateral (81%). Limitations include biopsy of only men with high-risk clinical features among PIRADS 1-2 MRI, potentially overestimating the csPCa CDR. CONCLUSIONS: The study cohort demonstrated generalizability of PRECISION findings. Applying the PRECISION biopsy strategy greatly reduces GG1 CDR, while missing a small number of csPCa, typically small volume, low-risk, and GG2. Missed csPCa are predominantly ipsilateral to MRI target, possibly representing targeting error