Complementary detection of clinically significant prostate cancer by magnetic resonance imaging fusion-targeted and systematic transrectal ultrasound-guided biopsy: influence of prostate-specific antigen and prostate-specific antigen density in a retrospective paired cohort.

BACKGROUND: Multiparametric magnetic resonance imaging (MRI)-targeted biopsy has improved prostate cancer detection, yet the relative diagnostic contributions of MRI-fusion-targeted biopsy and systematic transrectal ultrasound-guided (TRUS) biopsy across prostate-specific antigen (PSA) and PSA density (PSAD) levels remain uncertain. We evaluated the incremental detection of clinically significant prostate cancer (csPCa) between these techniques. METHODS: This retrospective single-center paired cohort study included 376 men with biopsy-proven prostate cancer who underwent both MRI fusion-targeted and 12-core systematic TRUS biopsy in the same session for a Prostate Imaging Reporting and Data System ≥3 lesion. csPCa was defined as International Society of Urological Pathology Grade Group ≥2. Detection was compared overall and across PSA strata (<4, 4-10, 10.01-20, 20.01-50, >50 ng/mL) and PSAD groups (<0.10, 0.10-<0.15, ≥0.15 ng/mL/cc) using exact McNemar testing on discordant pairs. RESULTS: Overall prostate cancer detection was similar between MRI fusion-targeted and systematic TRUS biopsy (318/376, 84.6% vs. 316/376, 84.0%; P = 0.927). csPCa was detected in 226/376 patients (60.1%) by MRI fusion-targeted biopsy and 212/376 (56.4%) by systematic biopsy; 60 MRI-only and 46 systematic-only discordant cases were observed (P = 0.206). MRI fusion-targeted biopsy showed numerically higher csPCa detection across the intermediate PSA range (4-50 ng/mL), with the largest absolute difference of 9.1 percentage points at PSA 20.01-50 ng/mL (n = 33); no PSA-stratified comparison reached statistical significance. csPCa detection increased with PSAD for both techniques across all three PSAD strata. CONCLUSION: MRI fusion-targeted and systematic TRUS biopsies were complementary for csPCa detection. MRI fusion-targeted biopsy showed a numerical advantage in the intermediate PSA range, while csPCa detection increased with PSA density for both techniques. These findings support risk-stratified interpretation of biopsy yield and do not support routine omission of systematic cores when MRI-fusion-targeted biopsy is performed.