Introduction: 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.
Evidence acquisition: 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.
Evidence synthesis: 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.
Conclusions: 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.