Testing for two biomarkers in urine may help some men avoid having to undergo an unnecessary biopsy to detect a suspected prostate cancer, findings from a new study show.
In the NCI-supported study, researchers from Emory University in Atlanta and M.D. Anderson in Houston tested urine samples from men referred for a prostate biopsy for elevated levels of two biomarkers (RNA biomarkers called PCA3 and T2:ERG) that studies have shown are associated with aggressive prostate cancer. Restricting biopsies to only those men with elevated levels of either of the biomarkers would have reduced the number of these unnecessary biopsies by an estimated one-third to one-half, the researchers report May 18 in JAMA Oncology.
At the same time, this pre-biopsy screening approach would still “preserve the ability to detect the more aggressive cancers,” explained the study’s lead investigator, Martin Sanda, M.D., of the Emory University Winship Cancer Institute.
The PCA3 gene is expressed at high levels in prostate cancers, and a urine test for PCA3 RNA is commonly used in clinical practice to monitor for potential disease in men who have a negative biopsy following an abnormal PSA test or digital rectal exam, Dr. Sanda explained. There is also a urine test for T2:ERG, which is the result of a fusion, or translocation of parts of two different genes, TMPRSS2 and ERG. This translocation is found in approximately half of advanced prostate cancers. Currently, the T2:ERG test is only available at a few academic cancer centers.
Currently, there are hurdles to implementing this testing in everyday care, Dr. Sanda cautioned. But the study findings “clearly demonstrate” that testing for these biomarkers could help to address some of the limitations of the current paradigm for prostate cancer screening and early detection, he said. Implementing this pre-biopsy testing in clinical practice may not yet be practical because of the limited availability of the T2:ERG test.
One of the biggest challenges for researchers has been identifying a way to screen for prostate cancer that can differentiate between indolent and potentially life-threatening cancers. One approach being tested is to develop ways to better triage care decisions following an abnormal PSA test, including making more informed decisions about whether to pursue a biopsy. Prostate biopsies have risks, including pain, bleeding, and potentially serious infections. The resulting oversiagnosis and overtreatment of indolent prostate cancers identified via biopsy have their own harms and costs.
You may find it useful to discuss this article and genetic testing with your urologist if you are contemplating a prostate biopsy. For a full description of the study methodology, see the full article which appeared in the June Cancer News Bulletin published by the National Cancer Institute (NCI) of the National Institutes of Health (NIH).