The prostate cancer gene 3 (PCA3) urine test is superior to percent-free PSA in predicting prostate biopsy outcome, according to researchers.
They studied 463 men who had one or two negative prostate biopsies. Following digital rectal examination, first-catch urine was collected to measure PCA3 mRNA concentration and calculate PCA3 score. The investigators compared this score with biopsy outcome and compared the diagnostic accuracy of the PCA3 assay with that of percent-free PSA.
The positive repeat biopsy rate was 28%. The higher the PCA3 score, the greater the probability of a positive repeat biopsy. Using a PCA3 score cutoff of 35 had a greater diagnostic accuracy than percent-free PSA with a cutoff of 25%, the investigators reported in European Urology (online ahead of print).
Additionally, PCA3 score was significantly higher in men with high-grade prostate intraepithelial neoplasia (HGPIN) compared with men without HGPIN. It also was significantly higher in men with a Gleason score of 7 or higher than in men with lower Gleason scores and significantly higher in men with clinical stage T2 versus T1.