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

The combination of systematic biopsy and MRI-targeted biopsy remains recommended due to the risk of overlooking clinically significant prostate cancer. Omitting systematic biopsy is associated with the risk of missing clinically significant PCa and reduced ISUP concordance at radical prostatectomy. However, in the era of minimally invasive procedures, their role has been increasingly debated considering their suggested marginal added value with the evolution of MRI and biopsy technology.

To assess the risk of distant positive biopsies, Noujeim et al. recently developed an algorithm based on PI-RADS score and PSA density (PSAd) for detecting clinically significant prostate cancer in biopsies taken beyond 10 mm from the index MRI lesion. Three distinct subgroups were defined: "low-risk" (PI-RADS 3), "intermediate-risk" (PI-RADS 4 or PI-RADS 5 and PSAd <0.15), and "high-risk" (PI-RADS 5 and PSAd ≥0.15).

This study aims to evaluate the added value in clinically significant prostate cancer detection on side-specific systematic biopsy relative to MRI lesion and externally validate the Noujeim risk stratification model predicting the risk of clinically significant prostate cancer on distant biopsies. To seek answers, 4841 consecutive patients diagnosed by MRI-targeted and systematic biopsy for PI-RADS score ≥3 lesions were identified between January 2016 and April 2023 at fifteen European referral centers. A total of 2387 patients met the inclusion criteria and were included in the analysis.

Overall, the detection rate of clinically significant prostate cancer was 49%. Considering MRI-targeted biopsy as the reference, the added value in terms of clinically significant prostate cancer detection was 5.8% for systematic biopsy, 4.2% for ipsilateral systematic biopsy only, and 2.8% for contralateral systematic biopsy only. Only 35 patients (1.5%) exclusively had clinically significant prostate cancer on contralateral systematic biopsy (p<0.001). Considering patients with clinically significant prostate cancer on MRI-targeted and ipsilateral systematic biopsy, the upgrading rate (non-clinically significant prostate cancer to clinically significant) was 2% (20/961) using contralateral systematic biopsy (p<0.001).

The Noujeim model exhibited modest performance (AUC of 0.63) when tested using our validation set, with a detection rate of clinically significant prostate cancer on contralateral systematic biopsy of 5.2%, 12%, and 29% for patients classified in the low-, intermediate-, and high-risk categories.

In conclusion, the added value of contralateral systematic biopsy was negligible in terms of cancer detection and upgrading rates, and in selected patients, this part of the procedure can be avoided. The Noujeim model could be incorporated into the decision-making process regarding the appropriate prostate biopsy strategy.

Written by: Romain Diamand, MD, PhD, Department of Urology, Jules Bordet Institute - Brussels University Hospital, Université Libre de Bruxelles, Brussels, Belgium

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