Mp46-14 Looking Beyond Cancer Detection: Is Template Biopsy Better Than Trus Biopsy in Planning Nerve Sparing Robotic Radical Prostatectomy in the Multiparametric Mri Era?

Abstract

INTRODUCTION AND OBJECTIVES: Risk calculators to determine a man 0 s risk for clinically significant prostate cancer (csPCa) at biopsy are known to reduce unnecessary biopsies and overdiagnosis. Updating these tools with advances in research like the use of different growth patterns within Gleason 4 PCa and sub forms of PSA could potentially lead to improved performance. Here we extended the recently developed DRE-based ERSPC Rotterdam Prostate Cancer Risk Calculator including the cribriform growth pattern (RPCRC-cribriform) with the well-known 4Kscore. We assessed clinical impact in terms of reduction of unnecessary biopsies.METHODS: The RPCRC-cribriform is based on the latest International Society of Urological Pathology (ISUP) grading system combined with the presence of cribriform growth pattern (CR+) and/or intraductal carcinoma (IDC+) and delivers three probabilities: no cancer, indolent PCa (ISUP grade 1, ISUP grade 2 CR/IDC-), and csPCa (ISUP grade 2 CR/IDC+, ISUP grade 3). The 4Kscore combines four kallikrein biomarkers along with patient 0 s age. We assessed the predictive performance of the RPCRC-cribriform, and the 4Kscore-updated RPCRC-cribriform (4Kscore added as predictor) in a previously published 4Kscore cohort (2872 unscreened men from ERSPC Rotterdam, biopsy indication PSA 3.0) 1 . Decision curve analysis was used to evaluate the number of biopsies avoided between the RPCRC-cribriform nomogram with/without the 4Kscore.RESULTS: The 4Kscore-updated RPCRC-cribriform had a higher area under the curve (0.89) than the RPCRC-cribriform (0.87; p<0.01) in csPCa prediction. Decision curve analysis indicated a slight increase in clinical impact for the 4Kscore-updated RPCRC-cribriform model as compared to the RPCRC-cribriform, Figure 1. At a 5% risk csPCa, 4.9 biopsies per 100 men at risk could be avoided by adding 4Kscore next to the RPCRC-cribriform.CONCLUSIONS: The performance of the ERSPC Rotterdam risk calculator based on the new ISUP grading for biopsy outcome can be increased further with the addition of the 4Kscore. Gain in net benefit must be weighed against additional costs and availability of tests.