Performance of MR fusion biopsy, systematic biopsy and combined biopsy on prostate cancer detection rate in 1229 patients stratified by PI-RADSv2 score on 3T multi-parametric MRI.

Purpose: We analyzed the additional value of systematic biopsy (SB) to MR-Ultrasound fusion biopsy (MRgFbx) for detection of clinically significant prostate cancer (csPCa), as increased sampling may cause increased morbidity.

Materials and methods: This retrospective study cohort was comprised of 1229 biopsy sessions between July 2016 and May 2020 in men who had a Prostate Imaging-Reporting and Data System (PI-RADSv2) category ≥ 3 lesion on 3 Tesla multiparametric MRI (3TmpMRI) and subsequent combined biopsy (CB; MRgFbx and SB) for suspected prostate cancer (PCa). Cancer detection rates (CDR) were calculated for CB, MRgFbx and SB in the study cohort and sub-cohorts stratified by biopsy history and PI-RADSv2 category. For 927 men with unilateral MR-visible lesions, SB CDR was additionally calculated for contralateral (SBc) and ipsilateral (SBi) subcohorts.

Results: On CB, the CDR for csPCa was 54.8% (673/1229). CDR for csPCa was significantly higher for MRgFbx (50.0%, CI 47.1-52.8%) compared to SB (35.3%, CI 32.6-38.1%) for all PI-RADSv2 ≥ 3 categories (p < .05). The MRgFbx CDR for PI-RADSv2 categories 3, 4, and 5 were 81.5%, 88.5%, and 95.6% respectively. For unilateral lesion cases, significantly more csPCa was detected in the SBi compared to the SBc subcohort (30.1% (279/927) vs. 10.4%, (96/927), p < 0.001). The combination of MRgFbx and SBi detected csPCa in 97.0% (480) of the 495 csPCa detected by CB.

Conclusion: MRgFbx had a higher CDR for csPCa than SB. While CB detected more csPCa than either method alone, in patients with a PI-RADSv2 category of 5, MRgFbx approximated the performance of CB. In unilateral lesion cases, SBc provided minimal added benefit.