The optimal core number and site for MRI-targeted biopsy of prostate? A systematic review and pooled analysis

Prebiopsy multiparametric magnetic resonance imaging (mpMRI) has been increasingly utilized for patients of suspicious prostate cancer (PCa). However, the optimal core number and site for MRI-targeted biopsy have not been clearly elucidated.

A systematic search in Pubmed, Embase and Ovid up to June 2019 was conducted and we identified studies reporting detection details of every MRI-targeted core. The incremental diagnostic value of performing additional cores was pooled on per-lesion analysis. Our secondary outcome concentrated on detection accuracy for cores of different site within one lesion.

Five studies comprising 2291 patients were identified to elucidate the association between targeted core number and cancer detection rates. Adding the second core to the first one resulted in 19.8% (range: 13.6-26.7%) increase in the detection rate of clinically significant lesions, and adding the third one to the first two resulted in 11.5% (range: 7.8-14.3%) increase. The incremental value of adding the fourth or the fifth core was 6.0% (4.7%, 6.9%) and 4.1% respectively. Four studies arranging MRI-targeted biopsy of more than two cores in well-determined sequences indicated more positive cores with higher cancer grade through center of the lesions.

Increasing the number of samples per target from one to two, or two to three resulted in a nonnegligible incremental detection rate of clinically significant lesions, while obtaining more than 3 cores per target provided a diminished incremental value. And performing targeted cores accurately through center of the lesions may help improve diagnostic accuracy.