PROPOSe: A Real-life Prospective Study of Proclarix, a Novel Blood-based Test to Support Challenging Biopsy Decision-making in Prostate Cancer.

Prostate-specific antigen (PSA)-based detection of prostate cancer (PCa) often leads to negative biopsy results or detection of clinically insignificant PCa, more frequently in the PSA range of 2-10 ng/ml, in men with increased prostate volume and normal digital rectal examination (DRE).

This study evaluated the accuracy of Proclarix, a novel blood-based diagnostic test, to help in biopsy decision-making in this challenging patient population.

Ten clinical sites prospectively enrolled 457 men presenting for prostate biopsy with PSA between 2 and 10 ng/ml, normal DRE, and prostate volume ≥35 cm3. Transrectal ultrasound-guided and multiparametric magnetic resonance imaging (mpMRI)-guided biopsy techniques were allowed.

Serum samples were tested blindly at the end of the study. Diagnostic performance of Proclarix risk score was established in correlation to systematic biopsy outcome and its performance compared with %free PSA (%fPSA) and the European Randomised Study of Screening for Prostate Cancer (ERSPC) risk calculator (RC) as well as Proclarix density compared with PSA density in men undergoing mpMRI.

The sensitivity of Proclarix risk score for clinically significant PCa (csPCa) defined as grade group (GG) ≥2 was 91% (n = 362), with higher specificity than both %fPSA (22% vs 14%; difference = 8% [95% confidence interval {CI}, 2.6-14%], p = 0.005) and RC (22% vs 15%; difference = 7% [95% CI, 0.7-12%], p = 0.028). In the subset of men undergoing mpMRI-fusion biopsy (n = 121), the specificity of Proclarix risk score was significantly higher than PSA density (26% vs 8%; difference = 18% [95% CI, 7-28%], p < 0.001), and at equal sensitivity of 97%, Proclarix density had an even higher specificity of 33% [95% CI, 23-43%].

In a routine use setting, Proclarix accurately discriminated csPCa from no or insignificant PCa in the most challenging patients. Proclarix represents a valuable rule-out test in the diagnostic algorithm for PCa, alone or in combination with mpMRI.

Proclarix is a novel blood-based test with the potential to accurately rule out clinically significant prostate cancer, and therefore to reduce the number of unneeded biopsies.

European urology oncology. 2021 Jan 06 [Epub ahead of print]

Thomas Steuber, Isabel Heidegger, Mona Kafka, Martin A Roeder, Felix Chun, Felix Preisser, Rein-Jüri Palisaar, Julian Hanske, Lars Budaeus, Ralph Schiess, Thomas Keller, Axel Semjonow, Peter Hammerer, Lukas Manka, Thorsten Ecke, Christian Schwentner, Carsten Ohlmann

Martini-Klinik, University Hospital Hamburg-Eppendorf, Hamburg, Germany. Electronic address: ., Medical University Innsbruck, Department of Urology, Innsbruck, Austria., Copenhagen Prostate Cancer Centre, Department of Urology, Rigshospitalet Copenhagen, Copenhagen, Denmark., University Hospital Frankfurt, Department of Urology, Frankfurt, Germany., Department of Urology, Marien Hospital Herne, Ruhr-University Bochum, Herne, Germany., Martini-Klinik, University Hospital Hamburg-Eppendorf, Hamburg, Germany., Proteomedix AG, Zurich-Schlieren, Switzerland., ACOMED statistik, Leipzig, Germany., University Hospital Muenster, Dept. of Urology, Prostate Centre, Muenster, Germany., Academic Hospital Braunschweig, Braunschweig, Germany., Helios Hospital Bad Saarow, Bad Saarow, Germany., Diakonie-Klinikum Stuttgart, Stuttgart, Germany., Johanniter Krankenhaus Bonn, Department of Urology, Bonn, Germany.

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