Predictors of disparity between targeted and in-zone systematic cores during transrectal MR/US-fusion prostate biopsy.

Background: The combination of targeted and systematic biopsies during MR/US-fusion prostate biopsy improves cancer detection over either modality alone.

Objective: To identify factors associated with disparity in detection of prostate cancer between systematic and targeted biopsies in magnetic resonance imaging positive zones.

Design, Setting, And Participants: We retrospectively analyzed 171 men receiving initial MR/US fusion biopsy at our institution from 2015 to 2018.

Outcome Measurements And Statistical Analysis: Disparity was defined as positive targeted but negative systematic biopsy within an magnetic resonance imaging-positive zone (PIRADS 3+), or vice versa. Multivariable logistic regression was used to identify factors associated with disparity in detection of cancer on a per lesion basis.

Results And Limitation: Three hundred and fifty-five lesions were targeted. For any cancer and clinically significant prostate cancer (csPCa), 37 (10%) and 24 (7%) lesions were target positive/systematic negative, respectively, while 30 (8%) and 23 (6%) lesions were target negative/systematic positive. In multivariable analysis, anterior location (OR 4.1, 95% CI 1.5-11.4, P = 0.007) was associated with csPCa target positive/systematic negative disparity, while higher prostate volume (OR 1.14, 95% CI 1.0-1.29, P = 0.04) was associated with csPCa target negative/systematic positive disparity. Shorter distance from apex (OR 1.02, 95% CI 1.01-1.04, P = 0.02) was associated with target positive/systematic negative disparity for any cancer. Limitations included relatively limited sample size and lack of prostatectomy specimen as a gold standard.

Conclusions: Anterior or apical lesion location favors better disease capture on targeted biopsies. When doing systematic-only biopsies, surgeons may consider sampling the anterior zone separately.