Can the predictive value of multiparametric MRI for prostate cancer be improved by a liquid biopsy with SelectMDx?

ABSTRACT

Background: SelectMDx is a urinary biomarker test for determining prostate cancer risk.

Aim: In a group of patients with a biopsy proven prostate cancer (PCa) who had undergone a multi parametric Magnetic Resonance Imaging (mpMRI) and urinary biomarker test with SelectMDx, we studied the additive value of SelectMDx to mpMRI and correlated that to the radical prostatectomy histology.

Methods and results: Thirty-nine consecutive patients with a positive prostate biopsy were included in the study. They all had mpMRI and SelectMDx and underwent a radical prostatectomy. Overall, the mpMRI showed a PIRADS ≤3 lesion in seven cases out of the 39 patients. Significant lesions (PIRADS ≥4) were found in 32 cases (82%), that is, in 17 cases a PIRADS 5 lesion and in 15 cases a PIRADS 4 lesion. The mpMRI missed significant PCa in seven cases (18%) who had a PIRADS ≤3 lesion but had a significant PCa on final histology after RP. In our study, the positive predictive values of mpMRI were 97% and that of the SelectMDx was 100%.

Conclusion: In this real-life selected group of consecutive patients with a confirmed positive PCa biopsy and available mpMRI, the liquid biopsy test with SelectMDx, did not provide an additional information about the PCa clinical significance. The addition of SelectMDx was only found valuable in those patients who had a very high-risk PCa (ie, GS ≥8) who had a positive SelectMDx test outcome despite of a negative mpMRI outcome.