Comparison of the incidence of clinically significant prostate cancer in patients with isolated peripheral versus transitional zone PIRADS 3 lesions.

Abstract

We sought to investigate the association between isolated PIRADS 3 lesions of the transitional zone (TZ) versus the peripheral zone (PZ) and the incidence of clinically significant prostate cancer (csPCa) on systematic and targeted prostate biopsy (SB, TB). We retrospectively reviewed our tertiary institutional database of patients who underwent mpMRI-fusion followed by TB + SB between 2016 and 2021. We compared the incidence of csPCa (Gleason Grade Group ⩾ 2) in patients with solitary TZ-only PIRADS 3 and PZ-only PIRADS 3 on SB and TB. We excluded patients with (1)known PCa, (2)PIRADS 4-5 and/or (3)lesions in both TZ and PZ. T-tests, Chi-square tests, were conducted to compare between the groups. Of 1913 patients, we identified 110 with PZ-only and 38 with TZ-only PIRADS 3 lesions. 73 patients in PZ-only and 19 in TZ-only met inclusion criteria. No statistically significant differences were observed between PZ and TZ groups in terms of age, median prostate-specific antigen (PSA), prostate volume, median PSA-density, or median number of targeted cores obtained, all with p > 0.05.On SB, the incidence of csPCA was higher in patients with PZ rather than TZ PIRADS-3 lesions (10/73 vs 1/19, p = 0.28). Similarly, csPCA was more common in TB of PZ versus TZ PIRADS 3 lesions (7/73 vs 0/19, p = 0.33). Based on these results, the positive predictive values of PIRADS3 as a marker of csPCA were 5.3% and 0% for TZ lesions on SB versus TB, respectively, compared to 17.7% and 9.6% in the PZ. PIRADS 3 lesions are rarely associated with csPCA on SB and TB, particularly when located in the TZ, which is an important factor to consider when deciding on a biopsy in patients with isolated TZ lesions.