Comparison of Proclarix, PSA Density and MRI-ERSPC Risk Calculator to Select Patients for Prostate Biopsy after mpMRI

Abstract

Tools to properly select candidates for prostate biopsy after magnetic resonance imaging (MRI) have usually been analyzed in overall populations with suspected prostate cancer (PCa). However, the performance of these tools can change regarding the Prostate Imaging-Reporting and Data System (PI-RADS) categories due to the different incidence of clinically significant PCa (csPCa). The objective of the study was to analyze PSA density (PSAD), MRI-ERSPC risk calculator (RC), and Proclarix to properly select candidates for prostate biopsy regarding PI-RADS categories. We performed a head-to-head analysis of 567 men with suspected PCa, PSA > 3 ng/mL and/or abnormal rectal examination, in whom two to four core transrectal ultrasound (TRUS) guided biopsies to PI-RADS ≥ three lesions and/or 12-core TRUS systematic biopsies were performed after 3-tesla mpMRI between January 2018 and March 2020 in one academic institution. The overall detection of csPCa was 40.9% (6% in PI-RADS < 3, 14.8% in PI-RADS 3, 55.3% in PI-RADS 4, and 88.9% in PI-RADS 5). MRI-ERSPC model exhibited a net benefit over PSAD and Proclarix in the overall population. Proclarix outperformed PSAD and MRI-ERSPC RC in PI-RADS ≤ 3. PSAD outperformed MRI-ESRPC RC and Proclarix in PI-RADS > 3, although none of them exhibited 100% sensitivity for csPCa in this setting. Therefore, tools to properly select candidates for prostate biopsy after MRI must be analyzed regarding the PI-RADS categories. While MRI-ERSPC RC outperformed PSAD and Proclarix in the overall population, Proclarix outperformed in PI-RADS ≤ 3, and no tool guaranteed 100% detection of csPCa in PI-RADS 4 and 5.

Evaluation of Proclarix in the diagnostic work‐up of prostate cancer

“…15,17,18,29 When the manufacturer-recommended cut-off of 10% was applied, Proclarix would have missed only 6% of csPCa, while PSAD would have missed 41% csPCa. These results are consistent with recently published data by Campistol et al, 19 where Proclarix sensitivity outperformed PSAD by missing only 6, respectively, 23 out of 232 csPCa patients. However, Proclarix showed only moderate performance for the avoidance of unnecessary biopsies of men harbouring either only ciPCa or no cancer (specificity of 19%), meaning only 16 out of 85 unnecessary biopsies could have been avoided.…”

“…[15][16][17][18][19][20][21][22] One limitation of the available literature on the Proclarix test is that all papers relied upon the results of a 10-14 core systematic biopsy of the prostate with or without targeted biopsy core. 15,[18][19][20] Although this practice is typical in the prostate cancer biomarker literature, concerns remain regarding the accuracy of this somewhat limited method of sampling the prostate. 6,23 For example, at the time of radical prostatectomy, up to 30% of patients will be upgraded or downgraded following a 12-14 core biopsy.…”

“…13 This test, which incorporates serum total PSA (tPSA), free PSA (fPSA), cathepsin D (CTSD), thrombospondin 1 (THBS1) and patient age, 14 has been shown to detect csPCa with more favourable diagnostic performance characteristics as compared to percent fPSA (%fPSA) and the ERSPC risk calculator. [15][16][17][18][19][20][21][22] One limitation of the available literature on the Proclarix test is that all papers relied upon the results of a 10-14 core systematic biopsy of the prostate with or without targeted biopsy core. 15,[18][19][20] Although this practice is typical in the prostate cancer biomarker literature, concerns remain regarding the accuracy of this somewhat limited method of sampling the prostate.…”

“…Proclarix (Proteomedix AG, Switzerland) is a novel serum‐based assay that was developed to aid in the risk stratification of men with an elevated PSA level 13 . This test, which incorporates serum total PSA (tPSA), free PSA (fPSA), cathepsin D (CTSD), thrombospondin 1 (THBS1) and patient age, 14 has been shown to detect csPCa with more favourable diagnostic performance characteristics as compared to percent fPSA (%fPSA) and the ERSPC risk calculator 15–22 . One limitation of the available literature on the Proclarix test is that all papers relied upon the results of a 10–14 core systematic biopsy of the prostate with or without targeted biopsy core 15,18–20 .…”

Magnetic Resonance Imaging, Clinical, and Biopsy Findings in Suspected Prostate Cancer

“…As such, ancillary clinical data have been proposed to complement MRI to minimize the number of unnecessary biopsies. This concept has been recently expanded by numerous studies, and several MRI-based risk models and strategies have been developed to guide decisions on prostate biopsy . However, it has been challenging to integrate the proposed approaches into clinical practice owing to considerable inconsistencies among them.…”