Ipsilateral versus full systematic sampling combined with cognitive MRI-targeted biopsy for prostate cancer detection in biopsy-naïve men with unilateral mpMRI lesions: a retrospective paired cohort study

Abstract Background To evaluate whether restricting systematic biopsy to the ipsilateral side of a unilateral multiparametric magnetic resonance imaging (mpMRI) lesion, in combination with cognitive MRI-targeted biopsy, affects the detection of clinically significant prostate cancer (csPCa) in biopsy-naïve patients. Methods This retrospective single-center cohort study included biopsy-naïve men with a single unilateral mpMRI lesion with Prostate Imaging Reporting and Data System (PI-RADS) score ≥ 3 who underwent cognitive MRI-targeted biopsy (3–4 cores) combined with systematic biopsy (10–12 cores) between June 2022 and June 2025. Ipsilateral systematic biopsy (ISBx) was defined as the subset of systematic cores from the same prostatic lobe as the MRI lesion. Clinically significant prostate cancer (csPCa) was defined as International Society of Urological Pathology (ISUP) grade group ≥ 2. McNemar’s test was used to perform paired comparisons between the standard approach (TBx + SBx) and the alternative strategy (TBx + ISBx). Miss rate and added detection rates were calculated from discordant pairs. Results Eighty-six patients were included. Overall, prostate cancer was detected in 69.8% of cases. Detection of csPCa was similar between TBx + SBx and TBx + ISBx (33.7% vs. 32.6%, p = 1.00). One additional csPCa was detected by the full systematic approach (miss rate 3.4%; added detection rate 1.2%). In contrast, the full systematic approach detected more clinically insignificant prostate cancer (ciPCa) (36.0% vs. 29.1%, p = 0.031), with a miss rate of 19.4% for ciPCa. Conclusions Restricting systematic biopsy to the ipsilateral side in combination with cognitive MRI-targeted biopsy was associated with similar detection of clinically significant prostate cancer, while reducing detection of clinically insignificant disease. Further prospective studies are needed to confirm these findings.