Optimizing Combined Magnetic Resonance Imaging (MRI)-Targeted and Systematic Biopsy Strategies: Sparing the Multiparametric MRI-Negative Transitional Zone in Presence of Exclusively Peripheral Multiparametric MRI-Suspect Lesions.

Purpose: We assessed whether sampling of the transitional zone can be spared in patients with exclusively peripheral prostate cancer (PCa)-suspicious multiparametric magnetic resonance imaging (mpMRI) lesions who undergo combined mpMRI targeted (TBx) and systematic prostate biopsies (SBx).

Materials And Methods: Of 1,685 patients who underwent extended SBx including transitional zone sampling and had TBx of ≥1 lesion in the peripheral and/or transitional zone, we selected 863 patients with exclusively peripheral PCa-suspicious lesions and negative transitional zone mpMRI. Clinically significant PCa (csPCa) was defined as Gleason score (GS) ≥3+4. Within the selected cohort we performed a retrospective head-to-head comparison of csPCa detection rates between biopsy protocols: A) combination of peripheral TBx plus extended SBx including transitional zone sampling vs B) peripheral TBx plus SBx without any transitional zone sampling. Analyses were complemented with multivariable logistic regression models (LRMs) in the total cohort for predicting csPCa in SBx transitional zone sampling.

Results: Compared to the extended protocol (A), omission of systematic transitional zone sampling (B) yielded similar PCa detection for csPCa (48% vs 47%) and GS 3+3 (21% vs 20%). Only 2.0% csPCa was additionally detected with transitional zone SBx sampling (A). LRM confirmed that intraprostatic zonal distribution of mpMRI lesions independently influences csPCa detection rates of transitional zone SBx sampling.

Conclusions: A peripheral TBx plus SBx without any transitional zone sampling protocol (B) yields similar csPCa detection rates as the standard extended protocol (A) but may reduce biopsy-related morbidity. This zone-dependent biopsy strategy warrants prospective evaluation to optimize the extent of systematic biopsies in presence of suspicious mpMRI lesions.