Purpose: To determine the added cancer detection rate (CDR) for clinically significant (csPCa) and all prostate cancer (PCa) of contralateral and ipsilateral systematic biopsy (SB) cores as compared to unilateral Transrectal MR-US fusion biopsy (MRgFbx) for 3Tmultiparametric MRI (3TmpMRI) detected lesions. 

Methods and Materials: With IRB approval and HIPAA compliance, the single arm, observational study cohort comprised 767 consecutive biopsies in 737 men with unilateral 3TmpMRI detected lesions (men with mid-line or bilateral targets were excluded) who subsequently underwent Combined biopsy (CB; both MRgFbx and SB) for suspected PCa, with ≥8 SB cores. 3TmpMRI was performed without endorectal coil on a Siemens Scanner (Siemens Healthineers, Malvern, Pa). MRgFbx was performed on the Artemis System (Eigen, Grass Valley, CA) and the 3D targeted and systematic cores were reviewed and analyzed.  SB CDR was subdivided into contralateral (SBc) and ipsilateral (SBi) subcohorts and csPCa was defined as Gleason Grade Group 2 or higher. CDR were calculated for CB, and the MRgFbx, SBc and SBi subcohorts.  Significance of differences was determined by the McNemar’s test with continuity correction.

Results: In the study cohort, an average of 11.6 SB cores were obtained, with 1-3 3TmpMRI targets/patient, and an average of 4.7 biopsy cores/MR target. In the CB cohort csPCa was detected in 60.2% (462/767) of biopsy cores.  The MRgFbx subcohort CDR for csPCA was  significantly higher than the SB subcohort alone (54.2% (416/767) vs 37.0% (284/767), p < 0.001). Significantly more csPCa was detected in the SBi compared to the SBc subcohort (30.9%  (237/767) vs. 12.1%, (93/767), p < 0.001).

Of the csPCa detected on CB cohort, 10.0% (46/462) were missed by MRgFbx but detected by SB. Of these, 30 (6.5%), 14 (3.0%), and 2 (0.4%) were detected only by SBi, SBc, and both respectively. Overall, the combination of MRgFbx and SBi detected csPCa in 97.0% (448) of the 462 cores detected by CB. 

Conclusions: The combination of MRgFbx and a wider ipsilateral systematic biopsy detected 97% of csPCa detected on CB, suggesting that high csPCa detection rates may be obtained with less overall sampling and morbidity.