Standardization of multi-parametric MRI (mp-MRI) prior to prostate biopsy and the incorporation of ultrasound fusion allowed precise and accurate targeted prostate biopsies. Random biopsies, still performed as routine, are taken from the ipsilateral and contralateral side of the prostatic lesion. We aim to determine the added value of combined biopsies (random biopsies plus target) compared to targeted biopsy only in patients with a single lesion on mp-MRI.

A total of 464 patients had Trans-perineal biopsies with MR fusion using the Koelis Machine, 196 patients had a single unilateral MRI lesion underwent target and random biopsy at our institution between July 2019 and January 2024. Biopsy results of Target biopsy alone (TB), Combined biopsy (CB) (targeted and random cores from both sides), TB+ipsilateral-random biopsy (TB+ipsi), and TB+contralateral-random biopsy (TB+contra) were analyzed. The relative contribution of these biopsy sites to the detection of significant prostate cancer was identified using targeted biopsy as a reference. McNemar test was used to compare cancer detection based on the location of the random biopsy.

The cancer detection rate in TB alone was 54.6% compared to CB (58.7%) (p= 0.005). Also, TB+ipsi had a detection rate of 56.6% (p= 0.046) and TB+contra of 57.1% p=0.025 when compared to TB alone. For clinically significant prostate cancer (csPCa), only CB and TB+contra showed significant increase in cancer detection (p value: CB= 0.01, TB+contra=0.046) when compared to TB alone as shown in table 1. When comparing TB, CB, TB+Ipsi, TB+contra according to the PIRADS score of the single lesion, there was no significant difference in patients with a single PIRADS 5 or PIRADS 3 lesion. However, there was a significant difference in cancer detection among patients with PIRADS 4 (p=0.018), in CB compared to TB as will be shown in table 2.

CB and TB+contra seem to have a benefit in diagnosis of clinically significant prostate cancer in patients with a single lesion detected on mp-MRI. CB seems to have a significant benefit in the diagnosis of prostate cancer in patients with a single PIRADS 4 lesion on mp-MRI, however there is no benefit from taking random biopsies in patients with a single PIRADS 5 lesion.