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

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

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

We retrospectively analyzed 171 men receiving initial MR/US fusion biopsy at our institution from 2015 to 2018.

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.

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.

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.