PCA3 urine test shows promise for PCa detection

A urine test that is under development appears to show significant specificity when used to detect prostate cancer, according to a multi-institution study from researchers in Colorado, Pennsylvania, New York, and Virginia presented at the AUA annual meeting in San Francisco.

"These results will help develop a new paradigm for the early detection of prostate cancer," said E. David Crawford, MD, of the University of Colorado, Denver, and the principal investigator on the study.

The prospective, community urologist-based clinical trial evaluated the PCA3 test using 1,994 urine samples from men with elevated serum PSA (about 2.5 ng/mL) and/or an abnormal digital rectal examination. Out of the samples, 1,946 had enough prostatic cells for PCA3 testing.

After analyzing the samples, researchers determined that 816 patients (42%) had prostate cancer with an average Gleason score of 7. Another 219 cases (11%) had only high-grade prostatic intraepithelial neoplasia and/or atypical small acinar proliferation suspicious for cancer, and 911 cases (47%) were benign.

The mean PCA3 value in men with prostate cancer was significantly higher than in those without cancer (50 vs. 25). The researchers concluded that PCA3 score was associated with the presence of cancer, Gleason score, and cancer volume. Using a cutoff value of 35, PCA3 had an odds ratio of 3.4 for predicting prostate cancer, compared with an odds ratio of only 1.7 for PSA. PCA3 had a specificity of 78% and a sensitivity of 49% for the diagnosis of prostate cancer, while the specificity and sensitivity for serum PSA were 21% and 87%, respectively.

"This relatively new urine marker is more specific than PSA for prostate cancer detection, potentially allowing fewer unnecessary prostate biopsies in men suspected of having prostate cancer," said Christopher Amling, MD, an AUA spokesman.