The PSA (prostate specific antigen) blood test has been criticized for years for driving men to seek biopsies and then definitive treatment for slow-growing cancers that may not pose a danger.
At the recent AUA meeting in New Orleans, urologist Martin Sanda presented results from research on tests that could allow the urology field to move beyond the PSA test as it is now. Winship magazine’s cover storyÂ has more on this topic.
Right now, only about a sixth of men who have a biopsy based on the results of a PSA test have something that doctors agree should be called a cancer (a tumor with a Gleason score of seven or higher).
Sanda described studies on a urine test that could double that specificity, possibly eliminating unnecessary biopsies for many men. He and his co-authors conclude:
Use of combined urinary testing for TMPRSS2:Erg and PCA3 to determine who should undergo prostate biopsy can avert unnecessary biopsy in 49 percent of men while retaining 95 percent sensitivity in detecting aggressive prostate cancer.
This research, involving more than 500 patients each in both primary and validation cohorts, was undertaken by the NCIâ€™s Early Detection Research Network and has also been publicized by the University of Michigan.
The urine test looks for two RNA markers. A test for one of the markers, PCA3, a gene that is hyperactivated in prostate cancer, is already FDA-approved for men who are considering a repeat biopsy after an initial negative result. The other marker, called TMRPSS2-ERG or T2-ERG for short, is a DNA alteration that is present in about half of all prostate cancers.
While this urine RNA test provides a substantial increase in specificity, there is still room for improvement. That could come from Emory/Winship researcher Carlos Moreno, who has been investigating the RNA markers of recurrent prostate cancer. His team is now looking for the same â€œsignatureâ€ of aggressive cancers in biopsy and urine samples.
Also at the AUA meeting, Sanda reported on studies of the PHI (Prostate Health Index), a commercially available blood test that is a refinement of the PSA test.
Caveat: these tests are commercially available (and there is industry involvement), studies of cost-effectivenessÂ are ongoing and the UK’s health care cost control agency recently decided against PHI and the PCA3 test (by themselves).