PD53-04 THE SELECTMDX URINARY-BIOMARKER TEST

Abstract

INTRODUCTION AND OBJECTIVE: To identify high-grade prostate cancer (PCa) in men with suspicion of PCa, as well as to minimize the number of diagnostic procedures and overdetection of low-grade PCa, reliable diagnostics tests, such as imaging and biomarker-based tests, are needed. To evaluate the SelectMDx urine test in biopsy-naïve men for the detection of high-grade PCa. Subsequently, combinations of the SelectMDx test with multi-parametric (mp)MRI and the potential impact on biopsy strategy were assessed. METHODS: A prospective multicenter study including 599 biopsy-naïve patients with a prostate specific antigen value (PSA) ≥3 ng/ml. All patients underwent a SelectMDx test, pre-biopsy mpMRI and systematic transrectal ultrasound-guided biopsy (TRUSGB). Patients with a suspicious mpMRI also underwent MR-guided biopsy (MRGB). The histopathologic outcome of combined biopsies (i.e. TRUSGB and MRGB) was used. High-grade PCa was defined as ISUP Grade group (GG) ≥2. Decision curve analysis (DCA) was performed to assess clinical utility. RESULTS: The rate of high-grade PCa was 31% (183/599). In this study, 62% (372/599) of patients had a positive SelectMDx test of which 44% (165/372) had GG≥2. The SelectMDx test could avoid 38% (227/599) of biopsies, at the risk of missing 8% (18/227) high-grade PCa. Ninety-eight percent of patients with a negative SelectMDx test and nonsuspicious mpMRI (joint approach) did either not have PCa (133/165) or had low-grade PCa (GG1) (29/165), this strategy could prevent 28% (165/599) of biopsies. Restricting biopsy to patients with a positive SelectMDx test and suspicious mpMRI (conditional approach) would reduce the number biopsies by 60% (357/599), at the risk of missing 7% (24/357) high-grade PCa. DCA showed highest net benefit for a joint approach at risk thresholds between 5-11%. A conditional strategy had the highest net benefit at risk thresholds >11%. CONCLUSIONS: he use of the SelectMDx test in detection of high-grade PCa results in reduction of both unnecessary biopsies and overdetection of low-grade PCa, at the cost of missing 8% of high-grade PCa. Combining the SelectMDx test with mpMRI in various strategies, results in further improvement of diagnostic performance. Source of Funding: This study was financed by a KWF Kankerbestrijding-Alpe’dHuZes grant (KUN 2015-6707) “4M: Met Prostaat MRI Meer Mans” (Dutch Trial Register identifier NTR5555) and was also supported by Guerbet (Paris, France).