Optimizing multiparametric magnetic resonance imaging-targeted biopsy and detection of clinically significant prostate cancer: the role of perilesional sampling.

Background: The added-value of systematic biopsy (SB) in patients undergoing magnetic resonance imaging (MRI)-targeted biopsy (TB) remains unclear and the spatial distribution of positive cores relative to the MRI lesion has been poorly studied. The aim of this study was to determine the utility of perilesional biopsy in detecting clinically significant prostate cancer (csPCa).

Methods: We enrolled 505 consecutive patients that underwent SB and TB for suspicious MRI lesions (PI-RADS score 3-5) at Jules Bordet Institute between June 2016 and January 2022. Patient-specific tridimensional prostate maps were reviewed to determine the distance between systematic cores containing csPCa and the MRI index lesion. Primary outcomes were the cancer detection rate (CDR) per patient and the cumulative cancer distribution rate of positive cores for each 5 mm interval from the MRI index lesion. The secondary outcome was the identification of risk groups for the presence of csPCa beyond a 10 mm margin using the chi-square automated interaction detector (CHAID) machine learning algorithm.

Results: Overall, the CDR for csPCa of TB, SB, and combined method were 32%, 25%, and 37%, respectively. While combined method detected more csPCa compared to TB (37% vs. 32%, p < 0.001), no difference was found when TB was associated with perilesional sampling within 10 mm (37% vs. 35%, p = 0.2). The cumulative cancer distribution rate for csPCa reached 86% for the 10 mm margin. The CHAID algorithm identified three risk groups: (1) PI-RADS3 ("low-risk"), (2) PI-RADS4 or PI-RADS5 and PSA density <0.15 ng/ml ("intermediate-risk"), and (3) PI-RADS 5 and PSA density ≥0.15 ng/ml ("high-risk"). The risk of missing csPCa was 2%, 8%, and 29% for low-, intermediate- and high-risk groups, respectively. Avoiding biopsies beyond a 10 mm margin prevented the detection of 19% of non-csPCa.

Conclusions: Perilesional biopsy template using a 10 mm margin seems a reasonable alternative to the combined method with a comparable detection of csPCa. Our risk stratification may further enhance the selection of patients.