New Urine Test for Prostate Cancer Helps Identify Risk
Researchers have developed a new urine test which can help doctors better determine which men are at a high risk for prostate cancer.
The test detects the presence of specific genes that are common in most prostate cancer cases, allowing doctors to classify patients into either low, intermediate or high risk categories and determine the best course of action.
"This is a tool that men and their physician can use to help them decide whether it's appropriate to get a biopsy now or delay that decision," said Dr. Scott Tomlins, lead researcher and a pathology resident at the University of Michigan Health System.
The current screening method for prostate cancer is a blood test called the “prostate-specific antigen” test which identifies elevated levels of this tumor marker in your blood. Each year more than a million men undergo prostate biopsies as a result of the PSA test, however only 25-35% of these men actually have prostate tumors. This high rate of false-positives create a huge amount of unnecessary testing, financial cost, and anxiety for men. Furthermore, researchers have been unable to prove whether or not the test is really worth all the cost.
“Using the PSA test to screen men for prostate cancer is controversial because it is not yet known for certain whether this test actually saves lives,” reads the website of the National Cancer Institute. “Moreover, it is not clear that the benefits of PSA screening outweigh the risks of follow-up diagnostic tests and cancer treatments. For example, the PSA test may detect small cancers that would never become life threatening. This situation, called over-diagnosis, puts men at risk of complications from unnecessary treatment”
For this reason more accurate screening methods, like the new urine test, have been widely sought after by researchers.
The scientists who developed the new urine test used the work based on a 2005 study which identified two specific genetic changes that occur in more than 50% of all prostate cancer cases known as TMPRSS2 and ERG. These genes cause an excess production of a protein which can be detected in the urine by the test.
In a clinical trial of 1,312 participants researchers used the results from the urine test to classify the men into either low, intermediate or high risk groups. After performing biopsies, cancer was found in 21% of the low-risk group, 43% of the intermediate group and 69% of the high risk group. In addition, the size and aggressiveness of the tumors correlated with the results of the urine test.
Currently, the researchers are recommending that this type of test could be used after a PSA to better determine which men should undergo a biopsy.
This prostate cancer urine test is currently still in development and more research is needed to determine the exact benefit of the tests. It is also unlearn what the cost of this test would be and whether it would translate to cost-savings for patients.
The study was published in the August 3 edition of the journal Science Translational Medicine.