Does the Accuracy of Prostate-specific Antigen Density in Identifying Clinically Significant Prostate Cancer Change with Prostate Volume?

Abstract

Background and objective: Prostate-specific antigen density (PSAD) can improve the accuracy of the prostate cancer (PCa) diagnostic pathway when combined with multiparametric magnetic resonance imaging (mpMRI). However, it is unknown how the risk of clinically significant PCa (csPCa) at each PSAD value varies according to prostate volume in patients with positive mpMRI findings (Prostate Imaging-Reporting and Data System [PI-RADS] score ≥3).

Methods: The study included 1731 patients with positive mpMRI findings who underwent MRI-targeted biopsy (TBx) plus systematic biopsy (SBx). The predicted risk of csPCa as a function of PSAD was plotted to explore how the appropriate PSAD cutoff varies according to prostate volume.

Key findings and limitations: Overall, 30%, 48%, and 22% of patients had PI-RADS 3, 4, and 5 lesions, respectively. csPCa was diagnosed in 56% of patients. Overall, the median predicted risk of csPCa corresponding to PSAD of 0.10 ng/ml/ml was 37% for prostate volume <45 ml, and 15% for prostate volume between 60 and 100 ml. For PI-RADS 3 lesions, patients with a prostate volume <40 ml had csPCa risk of >10% irrespective of their PSAD. For prostate volume >40 ml, the PSAD cutoff corresponding to csPCa risk of 10% varied between 0.10 and 0.15 ng/ml/ml. The main limitations of the study include the retrospective design and the tertiary referral center setting.

Conclusions and clinical implications: The predictive value of PSAD for csPCa detection varies according to prostate volume. The added value of PSAD in detecting csPCa in men with PI-RADS 3 lesions is greater for those with prostate volume >40 ml.

Keywords: Multiparametric magnetic resonance imaging; Prostate biopsy; Prostate cancer; Prostate volume; Prostate-specific antigen density.