Identifying More Aggressive Prostate Cancers with a New Urine Test

06 June 2024 1663
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Scientists may have developed a more efficient method to screen for the most severe and aggressive types of prostate cancer.

According to a study published in JAMA Oncology on April 18, a new test called MyProstateScore 2.0 (MPS2) has been introduced. This urine test screens for the 18 unique genes linked to high-grade prostate cancer.

Prostate cancer grades range from one to five based on their potential to grow and spread rapidly. The MPS2 test could potentially detect prostate cancers that fall into grade group two or higher, which are more perilous.

This test would be useful in distinguishing whether an individual's prostate cancer is low-grade (less risky) or high-grade (more risky), enabling doctors to sift through prostate cancer cases that don't require instant biopsy or intervention.

Dr. Mark Katz, clinical associate professor of urology at Boston University Chobanian and Avedisian School of Medicine, said that reducing unnecessary biopsies would be extremely beneficial, as they can cause pain, bleeding, and in rare cases, severe infection.

Further, MPS2 could decrease mental stress for men with low-grade prostate cancer by eliminating needless anxiety, doctor’s appointments, and procedures, according to Katz.

Next, we hear from experts on their thoughts on the new test and how it compares to existing prostate cancer screening methods.

Almost ten years ago, the same team from the University of Michigan developed the original version of the urine test named MPS. This early test detected two different genes linked with prostate cancer and measured a person's prostate-specific antigen (PSA) levels. PSA tests have been the go-to blood test for prostate cancer for many years.

Study author Dr. Arul Chinnaiyan, director of the Michigan Center for Translational Pathology at the University of Michigan Medical School, explained that the MPS2 is an improved version of the original test.

Chinnaiyan stated that MPS—version 1—and other commercial urine and blood biomarkers for prostate cancer perform well in detecting all forms of prostate cancer, but less effective in differentiating high-grade (grade group two) prostate cancer from low grade (grade group one) lazy disease. He added that the MPS2 is superior to other tests in pinpointing high-grade prostate cancer.

While perfecting this new test, Chinnaiyan’s team analyzed urine samples from men who had raised PSA levels or other irregular findings from rectal exams.

Scientists examined data from a development group, consisting of 761 men with an average age of 63 and identified the specific 18 genes that may suggest a high-grade prostate cancer.

The researchers then employed the 18-gene test to a validation group of 743 men. The study authors checked if the MPS2 could detect men with grade group two or higher cancers. The outputs showed that this enhanced test was more efficient at identifying intermediate and high-grade prostate cancers that require treatment, according to Katz.

Chinnaiyan elaborated that, across a patient population, the test may prevent around 40% of unnecessary biopsies. The test works well in patients who have had a prior negative biopsy, potentially preventing more than half of pointless biopsies.

This new urine test in practice could aid physicians in determining whether a patient with raised PSA levels truly requires additional intervention, says Katz.

Dr. Samuel Haywood, urologic oncologist at Cleveland Clinic, explained the dilemma clinicians and patients face with the elevated PSA test with further testing often being rather involved (such as MRI) or invasive like a biopsy. This test could help to further gauge patient’s risk and potentially reduce additional testing.

Haywood says the most widespread form of prostate cancer screening is the PSA blood test. However, he notes that the test isn't always accurate—many men might have raised PSA levels “for reasons that are not prostate cancer”.

Haywood points out that researchers are seeking ways to further establish a person’s actual risk of prostate cancer after undergoing a PSA test.

He added that finding more precise markers have been a focus in order to better screen men and reduce over-usage of more involved and invasive tests.

Haywood mentioned that doctors might use an MRI to further evaluate men with high PSA levels. However, he cautioned that these scans can sometimes overlook positive cases and may be expensive and hard to access.

Simple tests that check for other potential prostate cancer biomarkers have become alternative options. In addition to MPS2, blood and urine tests such as 4K, Prostate Health Index, PCA3, and others can provide more context to a person’s elevated PSA test, and can help guide treatment.

Though the study’s results are promising, there are limitations and questions that still remain.

For one, there was limited racial diversity in the study population pool, and the study authors noted it’s not yet clear whether the findings would be different in Black Americans.

This is especially significant because there are “some general differences” when it comes to prostate cancers found in Black and white patient populations, Chinnaiyan said. Specifically, Black men present with prostate cancer earlier, have more aggressive cases, and have higher mortality rates than white men.

“By having 18 biomarkers, we hope to mitigate those discrepancies,” he said. “That said, a future ongoing study will formally test MPS2 in a large African American cohort to confirm its performance further.”

The hope is that the MPS2 test would “behave similarly across all ethnic groups,” Haywood said, but at this point, there just isn’t data to back it up.

In addition to testing MPS2 in Black Americans, Chinnaiyan said he and his colleagues will also be looking at the use of this test “in the active surveillance population.” Essentially, they want to see if MPS2 can “predict which patients have aggressive prostate cancer, or whose cancer has progressed.”

For now, Chinnaiyan said anyone in the U.S. can access the test, which is owned by and available through LynxDx, a biotechnology lab in Michigan. MPS2 just “needs to be ordered by a physician,” he said, and some clinics are already fully set up to order the test.