Abstract: PD43-02
Sources of Funding: N Hansen has received a research grant from RWTH Aachen University Hospital (Aachen, Germany). T Barrett acknowledges support from Cancer Research UK, National Institute of Health Research Cambridge Biomedical Research Centre, Cancer Research UK and the Engineering and Physical Sciences Research Council Imaging Centre in Cambridge and Manchester and the Cambridge Experimental Cancer Medicine Centre. C Kastner acknowledges that he has received speaker or mentorship fees from Siemens Healthcare and MedCom GmbH. The Department of Urology, Addenbrookes Hospital, Cambridge, UK, also received sponsorship of various industry for organising Prostate MRI workshops. B Hadaschik acknowledges support from the German Research Foundation.

Introduction

To evaluate the detection rates of targeted and systematic biopsies in magnetic resonance (MRI) and transrectal ultrasound (US) image-fusion transperineal prostate biopsy for patients with previous benign transrectal US guided biopsies in two high-volume centres.

Methods

Two centre, prospective outcome study of 487 patients with previous benign biopsies that underwent transperineal MRI/US fusion-guided target and systematic saturation biopsy from 2012 to 2015. MRI was reported according to PIRADS Version 1. Detection of Gleason score (GS) 7-10 cancer (PCa) on biopsy was the primary outcome. Positive (PPV) and negative (NPV) predictive values including 95% confidence intervals were calculated. Detection rates of targeted and systematic biopsies were compared using McNemar test. AUCs were calculated for PIRADS, PSA-Density and the combination of the both.

Results

Median PSA was 9.0 (IQR 6.7-13.4) ng/ml. PIRADS 3-5 MRI lesions were reported in 343 (70%) patients. GS 7-10 PCa was detected in 149 (31%). PPV for detecting GS 7-10 PCa was 0.20 (+/-0.07) for PIRADS 3, 0.32 (+/-0.09) for PIRADS 4, and 0.70 (+/-0.08) for PIRADS 5. NPV of PIRADS 1-2 was 0.92 (+/-0.04) for GS 7-10 and 0.99 (+/-0.02) for GS 4+3 or higher cancer. Systematic biopsies alone found 125/138 (91%) GS 7-10 cancers. In patients with suspicious lesions (PIRADS 4-5) on MRI, systematic biopsies would not have detected 12/113 significant PCa (11%), while targeted biopsies alone would have failed to diagnose 10/113 (9%). In equivocal lesions (PIRADS 3), targeted biopsy alone would not have diagnosed 14/25 (56%) of GS 7-10, whereas systematic biopsies alone would have missed 1/25 (4%). Combination with PSA-density improved the AUC of PIRADS from 0.822 to 0.846.

Conclusions

In patients with high probability MRI lesions, combined targeted and systematic MRI/TRUS image-fusion biopsy is still required, however, systematic biopsy alone may be sufficient in patients with equivocal lesions. Repeated prostate biopsies may not be needed at all for patients with a low PSA-density and a negative MRI read by experienced radiologists.

Funding

N Hansen has received a research grant from RWTH Aachen University Hospital (Aachen, Germany). T Barrett acknowledges support from Cancer Research UK, National Institute of Health Research Cambridge Biomedical Research Centre, Cancer Research UK and the Engineering and Physical Sciences Research Council Imaging Centre in Cambridge and Manchester and the Cambridge Experimental Cancer Medicine Centre. C Kastner acknowledges that he has received speaker or mentorship fees from Siemens Healthcare and MedCom GmbH. The Department of Urology, Addenbrookes Hospital, Cambridge, UK, also received sponsorship of various industry for organising Prostate MRI workshops. B Hadaschik acknowledges support from the German Research Foundation.