As such, this group investigated the diagnostic performance of the PCA3 urine assay in predicting prostate cancer in Japanese men. They studied 489 men who underwent systematic extended prostate biopsy in Japan. Among these, 133 of them had repeat prostate biopsy. For PCA3 analysis, the Progensa assay was performed on urine specimens collected after digital rectal examination. The PCA3 score was calculated using PCA3 mRNA copy divided by PSA mRNA copy. PCA3 score was correlated with the biopsy outcome. The diagnostic accuracy of the PCA3 score was compared with the serum PSA and the free/total PSA ratio (%fPSA).
A total of 480 urine samples were collected and analyzed. Median age was 69 years and median serum PSA was 7.8ng/ml. Prostate cancer was detected in 195 men (40.6%). There was no significant relationship between serum PSA and PCA3 score. PCA3 score in patients with prostate cancer was significantly higher than that in those without (median 55 vs. 17, p<0.001). There was positive correlation between the probability of a positive prostate biopsy and the PCA3 score. Using a PCA3 cut-off value of 35.0, sensitivity, specificity and diagnostic accuracy were 67%, 72% and 70%, respectively (p<0.001). Area under the curve (AUC) for PCA3 score was 0.750 and AUC for serum PSA was 0.688. There was a significant performance difference as measured by the AUC for PCA3 score and serum PSA (p<0.05). In men with PSA levels between 4 and 10ng/ml, AUC for the PCA3 score was 0.750, for %fPSA 0.659, and for serum PSA 0.553. There was a significant difference in AUC between PCA3 score and %fPSA (p<0.05), as well as between PCA3 score and serum PSA (p<0.0001).
They concluded that the PCA3 test may help predict prostate cancer better than %fPSA in Japanese men with a worrisome PSA or clinical scenerio (such as a negative initial prostate biopsy).
Presented by Atsushi Ochiai, MD, PhD, et al. at the 26th Annual European Association of Urology (EAU) Congress - March 18 - 21, 2011 - Austria Centre Vienna, Vienna, Austria