With multi-parametric magnetic resonance imaging (mpMRI), MRI-fusion biopsy (MRFB) detects clinically significant prostate cancer (csPca) more effectively than transrectal ultrasound (TRUS)-guided systematic biopsy. However, current guidelines lack consensus on the optimal number of cores per lesion. This study aims to provide evidence-based recommendations for reducing the number of biopsy cores while maintaining optimal diagnostic efficacy.

From May 2023 to August 2024, we included patients who underwent MRFB with paired systematic biopsy, excluding those without a separately sampled first core, duplicates, or incomplete data. During MRFB, the first core of each target lesion was submitted separately, while the remaining targeted cores were grouped. For patients with multiple lesions, only the lesion with the highest PI-RADS score had its first core sampled separately. The diagnostic efficacy of the targeted first core, targeted remaining cores, and paired systematic biopsy in detecting prostate cancer was compared. Statistical analyses included descriptive statistics, the Mann-Whitney U test, the Kruskal-Wallis test, and the chi-square test to compare diagnostic efficacy. Logistic regression was performed to identify predictors of a positive first core result for prostate cancer (Pca) and csPca. All data were analyzed using MedCalc Statistical Software version 22.009.

The targeted first core biopsy demonstrated non-inferiority to the targeted remaining cores (3.17 ± 1.27 cores per lesion) across multiple metrics, including the Pca detection rate (45.1% vs. 52.2%, p = 0.29), csPca detection rate (29.2% vs. 33.6%, p = 0.47), Gleason score (6.94 vs. 6.90, p = 0.86), positive Pca percentage (43.1% vs. 41.3%, p = 0.72), and positive csPca percentage (28.1% vs. 28.1%, p = 0.87). Multivariate logistic regression identified age (OR = 1.15, 95% CI: 1.03–1.27, p < 0.001), serum PSA level (OR = 1.11, 95% CI: 1.03–1.20, p < 0.01), and PI-RADS score (OR = 4.26, 95% CI: 1.47–12.34, p < 0.01) as independent predictors of a positive first core biopsy result for csPca. Among patients meeting all three criteria—age ≥ 65 years, PSA ≥ 15 ng/mL, and PI-RADS ≥ 4—the targeted first core biopsy detected Pca in 100% and csPca in 94% of those ultimately diagnosed, demonstrating high diagnostic accuracy in this high-risk subgroup.

The targeted first core biopsy is non-inferior to the targeted remaining cores in detecting both Pca and csPca. In patients meeting all three criteria—age ≥ 65 years, PSA ≥ 15 ng/mL, and PI-RADS ≥ 4—two cores per lesion may be sufficient for accurate diagnosis during MRFB.