Is Systematic Biopsy Mandatory in Addition to Targeted Biopsy in Patients with a PI-RADS 5 Lesion Identified on Magnetic Resonance Imaging?

Abstract

Objective Most of the lesions classified as prostate imaging-reporting and data system (PI-RADS) 5 represent clinically significant prostate cancers; the utility of systematic biopsy (SB) in addition to magnetic resonance imaging-targeted biopsy (MRI-TB) is unclear. We evaluated clinically significant prostate cancer detection via SB, TB alone, and combined SB and TB in men with a PI-RADS 5 lesion. The aim of this study was to determine whether SB can be avoided in the case of PI-RADS 5. Materials and Methods Patients undergoing MRI-TB+SB with a PI-RADS 5 lesion were retrospectively reviewed in a prospectively collected database. Pathology obtained from the MRI-TB was then compared with that of the SB. All patients underwent multiparametric MRI followed by transrectal/transperineal TB of PI-RADS 5 lesion and 12-core SB. The prostate cancer and clinically significant prostate cancer (grade group >= 2) detection on SB, MRI-TB and MRI-TB+SB were determined for all men. A subgroup analysis of the combined group was also performed to identify performances of TB alone, SB alone, and combination of TB+SB for the prediction of final pathology at radical prostatectomy. Statistical significance was set at p<0.05. Results We identified PI-RADS 5 lesions in 315 patients. 199/315 men, were found to have prostate cancer. Of these, 163 cases were clinically significant. The detection rate of prostate cancer for MRI-TB+SB, MRI-TB and SB was 63%, 59% and 49%, respectively, and the detection rate for clinically significant prostate cancer was 51%, 48% and 37%, respectively. SB detected an additional 6.5% of any grade prostate cancer and 6.7% clinically significant prostate cancer over TB. A total of 89 patients had prostate specific antigen density >0.15 ng/mL. All patients with prostate-specific antigen density (PSAD) >0.28 had cancer of any grade. The clinically significant prostate cancer detection rate improved with increased PSAD for SB. Among 102 patients, 8 had upgraded pathology from MRI-TB+SB. MRI-TB and SB pathology of the PI-RADS 5 lesion separately predicted final pathology with 81% and 69% concordance, respectively. The the downgrade was lowest in both methods, but the upgrade was higher in SB. Conclusion In the presence of a PI-RADS 5 lesion, SB offers minimal additional but not negligible clinical value. The safety of omitting SB awaits further research.