More specific diagnostic for prostate cancer is needed to decrease overdetection and number of diagnostic procedures.

To assess the performance of combining a blood-based biomarker panel and magnetic resonance imaging (MRI)-targeted biopsies for prostate cancer detection.

We used a prospective, multicenter, paired diagnostic study design. A total of 532 men aged 45–74 yr referred for prostate cancer workup were included during 2016–2017.

Participants underwent blood sampling for analysis of the Stockholm3 test including protein biomarkers, genetic polymorphisms, and clinical variables; 1.5 T MRI; systematic prostate biopsies; and MRI-targeted biopsies to lesions with Prostate Imaging Reporting and Data System version 2 ≥3.

The main outcome was numbers of detected prostate cancer characterized by grade group (GG) and the number of performed biopsies using relative sensitivity (RS).

Median prostate-specific antigen was 6.3 ng/ml, and mean age was 63.9 yr. Targeted and systematic biopsies detected 170 and 162 GG ≥2 tumors, respectively (RS 1.05; 95% confidence interval [CI] 0.96–1.14). Compared with performing systematic biopsies on all men, performing targeted and systematic biopsies only on men with >10% risk of GG ≥2 cancer, as predicted by the Stockholm3 test, required 62% (95% CI 58–66) of the biopsy procedures and detected 58% (95% CI 48–70) of GG 1 disease, with increased sensitivity for GG ≥2 detection (RS 1.10; 95% CI 1.02–1.17). Performing only targeted biopsies in men with elevated Stockholm3 test altered these results only slightly. Compared with performing systematic and targeted biopsies on all men, performing this only for men with an elevated Stockholm3 test decreased detection of GG ≥2 cancer slightly (RS 0.92; 95% CI 0.88–0.95). Limitations include lacking knowledge of true disease prevalence.

These findings provide evidence that strategies combining the blood-based Stockholm3 test and MRI-targeted biopsies can be used to inform biopsy decision making.

In this study, 532 men coming for prostate cancer workup underwent blood sampling, and both traditional and magnetic resonance imaging/fusion-guided prostate biopsies. We report that performing targeted biopsies only in men with an elevated risk as assessed by the Stockholm3 test saved biopsies, decreased overdetection, and maintained the number of detected high-grade cancers.