Comparison of prostate cancer diagnostic models based on PCA3 and TMPRSS2:ERG RNA biomarkers from post-DRE and non-DRE urine specimens

Prostate cancer associated 3 (PCA3) and TMPRSS2:ERG fusion (T:E) are established urinary RNA biomarkers for detecting clinically significant prostate cancer (csPCa, Grade Group ≥ 2). Large within-subject paired studies directly comparing post-DRE and non-DRE urine collection are lacking. Using a multicenter cohort with samples collected from the same patients, we evaluated the effect of urine collection method on PCA3 and T: E diagnostic performance. In a multicenter prospective study paired post-DRE and non-DRE whole-urine samples were collected before systematic biopsy. PCA3, T:E, and reference PSA RNAs were quantified in 373 post-DRE and 355 non-DRE eligible specimens. Logistic regression models combining PCA3, T:E, PSA density, and age were developed for post-DRE (PD2) and non-DRE (ND2) cohorts and evaluated by cross-validated receiver operating characteristic (ROC) analysis and decision curve analysis. PD2 outperformed ND2 in discrimination (AUC 0.78 versus 0.73) and net benefit. At ~ 95% sensitivity, PD2 specificity was 32% versus 23% for ND2. In the paired-sample analysis (n = 333), adding PCA3 and T:E to clinical variables improved AUC from 0.70 to 0.80 for post-DRE urine (p = 0.003), while gains were non-significant for non-DRE urine. Post-DRE specimens showed markedly higher RNA yields (median ~ 20-fold higher PCA3 and T:E copy numbers). Post-DRE whole urine collection increased biomarker RNA yield and significantly improved csPCa diagnostic accuracy versus non-DRE whole urine. PCA3 and T:E provided meaningful additive value only in post-DRE specimens, supporting its preferred use. As biopsies were performed without MRI guidance, future studies in MRI-integrated pathways would further characterize clinical utility.