The Added Value of Side-specific Systematic Biopsy in Patients Diagnosed by Magnetic Resonance Imaging–targeted Prostate Biopsy

Background Systematic biopsy (SB) combined with magnetic resonance imaging (MRI)-targeted biopsy is still recommended considering the risk of missing clinically significant prostate cancer (csPCa). Objective To evaluate the added value in csPCa detection on side-specific SB relative to MRI lesion and to externally validate the Noujeim risk stratification model that predicts the risk of csPCa on distant SB cores relative to the index MRI lesion. Design, setting, and participants Overall, 4841 consecutive patients diagnosed by MRI-targeted biopsy and SB for Prostate Imaging Reporting and Data System score ≥3 lesions were identified from a prospectively maintained database between January 2016 and April 2023 at 15 European referral centers. A total of 2387 patients met the inclusion criteria and were included in the analysis. Outcome measurements and statistical analysis McNemar’s test was used to compare the csPCa detection rate between several biopsy strategies including MRI-targeted biopsy, side-specific SB, and a combination of both. Model performance was evaluated in terms of discrimination using area under the receiver operation characteristic curve (AUC), calibration plots, and decision curve analysis. Clinically significant prostate cancer was defined as International Society of Urological Pathology grade group ≥2. Results and limitations Overall, the csPCa detection rate was 49%. Considering MRI-targeted biopsy as reference, the added values in terms of csPCa detection were 5.8% (relative increase of 13%), 4.2% (relative increase of 9.8%), and 2.8% (relative increase of 6.1%) for SB, ipsilateral SB, and contralateral SB, respectively. Only 35 patients (1.5%) exclusively had csPCa on contralateral SB (p < 0.001). Considering patients with csPCa on MRI-targeted biopsy and ipsilateral SB, the upgrading rate was 2% (20/961) using contralateral SB (p < 0.001). The Noujeim model exhibited modest performance (AUC of 0.63) when tested using our validation set. Conclusions The added value of contralateral SB was negligible in terms of cancer detection and upgrading rates. The Noujeim model could be included in the decision-making process regarding the appropriate prostate biopsy strategy. Patient summary In the present study, we collected a set of patients who underwent magnetic resonance imaging (MRI)-targeted and systematic biopsies for the detection of prostate cancer. We found that biopsies taken at the opposite side of the MRI suspicious lesion have a negligible impact on cancer detection. We also validate a risk stratification model that predicts the risk of cancer on biopsies beyond 10 mm from the initial lesion, which could be used in daily practice to improve the personalization of the prostate biopsy.