A Phase II Prospective Blinded Trial of Magnetic Resonance Imaging and In-Bore Biopsy in Active Surveillance for Prostate Cancer.

Objective: To demonstrate the added benefit of multiparametric (mp)MRI risk stratification during active surveillance.

Methods: This prospective, single-arm, nonrandomized study included 82 men with low-risk prostate cancer (PCa). We compared two biopsy strategies in parallel. The first biopsy strategy was an in-bore and transrectal ultrasound (TRUS) biopsy in men with suspicious mpMRI findings. The second was a TRUS biopsy in all 82 men, blinded to the results of the previously performed mpMRI.

Results: We identified 27/82 men with suspicious mpMRI. Of those 27 men, we detected 8/27 with csPCa on biopsy, and we identified two men with in-bore biopsy exclusively, three men with TRUS biopsy exclusively, and three men with both biopsy strategies. Of the 55/82 men with nonsuspicious mpMRI (who only received TRUS biopsies), two men had csPCa. TRUS biopsy of the entire cohort of 82 men would have led to the correct diagnosis of 80% men with csPCa, requiring all 82 men to receive biopsies (csPCa in 10% of the 82 biopsies). Conducting in-bore biopsies plus TRUS biopsies in men with suspicious mpMRI would have also led to the detection of 80% of men with csPCa, requiring only 27 men to receive biopsies (csPCa in 30% of the 27 biopsies).

Conclusion: The combination of TRUS and in-bore biopsies, limited to men with suspicious mpMRI, resulted in a similar detection rate of csPCa compared to TRUS biopsies of all men but required only one-third of men to undergo biopsy. Our results indicate that in-bore and TRUS biopsies continue to complement each other.