Anyone who has learned a reasonable amount about the diagnosis and management of prostate cancer has learned that the prostate specific antigen or PSA test is not a particularly good test for identifying or monitoring the status of men with active prostate cancer. It is simply better than anything else we have. Researchers have been looking for better options for years.
An article by Deras et al. in this week’s issue of the Journal of Urology discusses her team’s recent research on the potential of a urinary assay for PCA3, an mRNA molecule that is highly overexpressed in prostate cancer cells.
Their research suggests that levels of PCA3 in urine may be “a useful adjunct” to other methods of testing for prostate cancer. Apparently, levels of PCA3 in urine are independent of prostate volume, PSA level, and number of biopsies that a patient may have had. Combining the results of PCA3 levels with those provided by PSA testing, measurement of prostate volume, and digital rectal examination (DRE) had significant impact on the ability to accurately predict the result of biopsies in a study involving 570 men.
This is hardly a big step forward, and it will likely be a while before we know if such a test is commercially viable, but anything that helps us to predict the probability of prostate cancer without having to do a biopsy offers a potentially useful opportunity.
Of course it would be much better if we could find one blood or urine test that was 100 percent selective and >90 percent specific for prostate cancer, but the chances of that are starting to look pretty low.