New Test Could Help Identify Aggressive Prostate Cancer

New Test Could Help Identify Aggressive Prostate Cancer

Researchers may have developed a new, improved way to test for the most serious and aggressive forms of prostate cancer.

A new study, published in JAMA Oncology on April 18, introduced the MyProstateScore 2.0 (MPS2) test. MPS2 is a urine exam that tests for 18 unique genes tied to high-grade prostate cancer.

Prostate cancers are given a “grade” from one to five based on how likely they are to quickly grow and spread. The MPS2 test may be able to identify prostate cancers that meet the criteria for grade group two or higher, which are more dangerous.

The ability to detect whether a person’s prostate cancer is low-grade (and less of a concern) or high-grade (and more of a concern) would help doctors filter out prostate cancer cases that don’t necessitate immediate biopsy or intervention.

“Being able to decrease the number of unnecessary biopsies would be very beneficial because they can sometimes be painful, cause bleeding, and most importantly, there is a small risk of severe infection,” said Mark Katz, MD, clinical associate professor of urology at the Boston University Chobanian and Avedisian School of Medicine.

Beyond just the physical, the MPS2 test could also provide peace of mind for men with low-grade prostate cancer, who might otherwise face unnecessary anxiety, doctor’s visits, and procedures, Katz told Health.

Here’s what experts had to say about the new test, and how it stacks up against other prostate cancer testing methods.

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Almost a decade ago, the same University of Michigan-based research team behind MPS2 devised an original version of the urine test, dubbed MPS. That earlier test examined two different genes associated with prostate cancer, as well as a person’s prostate-specific antigen (PSA) levels. PSA testing has been used for decades, as is considered the standard blood test to screen for prostate cancer.

But MPS2 improves upon the original version, explained study author Arul Chinnaiyan, MD, PhD, director of the Michigan Center for Translational Pathology at the University of Michigan Medical School.

“MPS—version 1—and some of the other commercial urine and blood biomarkers for prostate cancer tend to do well in detecting all forms of prostate cancer, but less so in detecting high-grade, [grade group two], prostate cancer from those with low grade, [grade group one], indolent disease,” Chinnaiyan told Health. “[MPS2] is superior to the other tests in detecting high-grade prostate cancer.”

While developing this new test, Chinnaiyan and his team looked at urine samples from men who had elevated PSA levels or other abnormal rectal exam findings.

Researchers used data from a development cohort—which included 761 men with an average age of 63—to pick out the specific 18 genes that may be indicative of a higher-grade prostate cancer.

The 18-gene test was then applied to a validation cohort of 743 men, where the study authors looked at whether MPS2 could identify those men with grade group two or higher cancers. Those results showed that the upgraded test was “better at identifying the intermediate and high-grade prostate cancers that require treatment,” Katz explained.

“Across a population of patients, the test prevents approximately 40% of unnecessary biopsies,” Chinnaiyan explained. “The test works even better in patients that have had a prior negative biopsy, and can prevent upwards of 50% of unnecessary biopsies in this group.”

In practice, this new urine test could help physicians determine whether a patient with elevated PSA levels really needs further intervention, said Katz.

“When faced with an elevated PSA test, patients and clinicians are faced with the tough decision about further testing that may be rather involved (such as MRI) or invasive, like a biopsy,” Samuel Haywood, MD, urologic oncologist at Cleveland Clinic, told Health. “This test aims to help further risk-stratify patients and potentially reduce additional testing.”

The most common form of prostate cancer screening is the PSA blood test, Haywood said. But the test isn’t perfect by any means—many men who are screened may have elevated PSA levels “for reasons that are not prostate cancer,” he explained.

Because of this, researchers have been looking for ways to further determine a person’s actual risk of prostate cancer after they take a PSA test, Haywood said.

“As a field, we have been trying to find more specific markers to help better screen men and reduce over-utilization of more involved [or] invasive testing,” he added.

One option is for doctors to use an MRI to further evaluate men with high PSA levels, Haywood said. However, he warned, these scans can sometimes miss positive cases, and can be costly 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.

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