A cohort of transperineal electromagnetically tracked magnetic resonance imaging/ultrasonography fusion-guided biopsy: assessing the impact of inter-reader variability on cancer detection

Objective To evaluate the ability to detect clinically significant prostate cancer (PCa) using a novel electromagnetically (EM) tracked transperineal magnetic resonance imaging (MRI)/ultrasonography (US) fusion-guided targeted biopsy (transperineal TBx) platform and the impact of inter-reader variability on cancer detection. Materials and Methods A total of 176 patients with suspicious lesions detected on multiparametric MRI (mpMRI) underwent a systematic modified Barzel template biopsy (12-core) transperineal biopsy (transperineal SBx) and transperineal TBx with EM tracking (UroNav; Philips Healthcare, Best, the Netherlands) in the same setting. Cancer detection rates (CDRs) were stratified by Prostate Imaging Reporting and Data System (PI-RADS) v2 scores and compared with Fisher's exact test. Area under the curve (AUC) was calculated for prostate-specific antigen (PSA), PSA density (PSAD), PI-RADS score, and subgroup analysis of individual readers' PI-RADS scores with respect to overall CDR and clinically significant CDR. Results The overall CDR was 76.7% (135/176), of which 76.3% (103/135) was clinically significant PCa. Among the 135 patients with PCa, transperineal TBx detected 90.4% of cases (122/135), either alone or in combination with transperineal SBx. The remaining 9.6% of cases (13/135) missed by transperineal TBx were diagnosed by transperineal SBx alone, of which three were clinically significant. Conversely, transperineal SBx missed 14% of cases (19/135), 14 of which were clinically significant PCa. Sensitivities for transperineal TBx and transperineal SBx were 90.4% and 85.9%, respectively. On a per-lesion basis, PI-RADS score (AUC 0.74) outperformed both PSA (AUC 0.59) and PSAD (AUC 0.63) in discriminating clinically significant from non-clinically significant PCa on transperineal TBx. Although not formally statistically tested, AUCs amongst different mpMRI readers appeared to display considerable variability. There were no adverse events, including sepsis. Conclusions Electromagnetically tracked transperineal TBx of MRI-visible lesions enhanced the ability of transperineal SBx to detect PCa, with greater sensitivity for clinically significant disease. These findings suggest transperineal TBx is a safe, alternative fusion platform for patients with a suspicious lesion on prostate MRI. The assessment of inter-reader variability, in conjunction with prediction of clinically significant PCa and CDR, is an important first step for quality control in implementing an MRI-based screening programme.