Urine test may determine prostate cancers' level of aggression

Researchers say they've developed a urine test that could answer whether prostate cancer is aggressive and requiring immediate treatment, or slow-growing and worthy of monitoring only. Photo by Adobe Stock/HealthDay News

When prostate cancer strikes, one question is paramount: Is it aggressive and requiring immediate treatment, or slow-growing and worthy of monitoring only?

Right now, an invasive biopsy is the only way to answer that query, but researchers say they've developed a urine test that could do the job instead.

The test, called MyProstateScore2.0 (MPS2), was developed by researchers at the University of Michigan, who reported their findings Thursday in the journal JAMA Oncology.

"If you're negative on this test, it's almost certain that you don't have aggressive prostate cancer," said Dr. Arul Chinnaiyan, a professor of pathology and urology at Michigan Medicine.

The approach to prostate cancer care has changed radically over the past few decades, noted study co-senior author Dr. John Wei.

"Twenty years ago, we were looking for any kind of [prostate] cancer," said Wei, a professor of urology at the university. "Now, we realize that slow-growing cancer doesn't need to be treated. All of a sudden, the game changed. We went from having to find any cancer to finding only significant cancer."

In decades past, the prostate-specific antigen (PSA) blood test was used routinely to help spot cancers. But its inefficiency in differentiating between aggressive and slow-growing tumors led to over-treatment, and the test is now used much less frequently.

Almost 10 years ago, University of Michigan researchers developed the first generation MyProstateScore test. It tracked two genes, TMPRSS2::ERG, that fuse together to cause prostate cancer, along with another cancer marker called PCA3.

That test was good, but maybe not quite good enough, Chinnaiyan said.

"There was still an unmet need with the MyProstateScore test and other commercial tests currently available," he explained. "They were detecting prostate cancer, but in general they were not doing as good a job in detecting high-grade, or clinically significant, prostate cancer. The impetus for this new test is to address this unmet need."

In the latest-generation test, the Ann Arbor team added analyses of 54 more genes -- all linked to aggressive prostate tumors -- into the mix. Further testing narrowed that list of genes down to 16, which are now included into MyProstateScore2.0.

Prostate cancers' level of aggression is measured on what's called the Gleason score, with tumors scoring as Gleason Grade Group 2 (GG2) or higher more likely to grow and spread than those rated Grade Group 1 (GG1), which may remain "indolent" for years.

The MyProstateScore2.0 test was found to be effective in spotting tumors with a GG2 or higher score, and was 100% effective in detecting GG1 stage tumors, the Michigan team said.

That means that a lot of men may not have to undergo invasive prostate biopsies, depending on their MPS2 results, the researchers said.

"Four of 10 men who would have a negative biopsy will have a low risk MPS2 result and can confidently skip a biopsy," Wei said.

"If a man has had a biopsy before, the test works even better," he added. That scenario might occur if a patient's PSA test numbers begin to rise over time.

"In those men who have had a biopsy before and are being considered for another biopsy, MPS2 will identify half of those whose repeat biopsy would be negative," Wei explained. "Nobody wants to say sign me up for another biopsy. We are always looking for alternatives and this is it."

Right now, the MPS2 test is only available via LynxDx, a University of Michigan spin-off company, which has a license from the university to commercialize the test.

More information

Find out more about prostate cancer detection at the U.S. Centers for Disease Control and Prevention.

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