An experimental urine test can detect aggressive prostate cancers in men on active surveillance, potentially sparing them from repeated biopsies, researchers reported on Friday.

The MPS2-AS test is based on the MyProstateScore 2.0 (MPS2), a commercially available assay from Lynx Dx that the FDA approved in 2024 to evaluate the risk for clinically significant prostate cancer. MPS2 can detect aggressive tumors diagnosed at Grade Group 3, or Gleason 4+3, or above, the point at which treatment is generally recommended over continued surveillance.

Blood and urine tests are used to determine if patients have elevated levels of prostate-specific antigen (PSA), which can indicate prostate cancer. This month, the FDA granted premarket approval to IsoPSA, a blood test from Cleveland Diagnostics, to help men older than 50 years with high PSA levels decide whether to undergo a prostate biopsy.

Biopsies have predictable short‑term side effects — mostly bleeding and urinary symptoms — and clinically meaningful risks for infection, including rare sepsis or serious bleeding that may require hospitalization.

The new study found that use of the urine test could avoid up to 67% of unnecessary prostate biopsies while still detecting 93% of higher-grade tumors, according to the researchers, who presented the findings at the 2025 annual meeting of the Society of Urologic Oncology.

Jeffrey Tosoian, MD, MPH, an assistant professor in the Department of Urology at Vanderbilt University in Nashville, Tennessee, who helped conduct the study, said, “The goal is simple: Keep active surveillance safe, while reducing the burden associated with accurate monitoring. A urine test that can flag higher-grade cancer moves us closer to that reality.”

Compared to the current clinical approach, in which all patients are recommended to undergo routine biopsies during surveillance, “this research suggests it may be possible to use a noninvasive molecular urine test to identify better who needs a biopsy and who can safely defer one,” he added.

Todd Morgan, MD, a professor of urology at the University of Michigan in Ann Arbor, Michigan, who helped conduct the study, said he was “blown away” by the results.

“I’m very cautious about this space by nature. Many biomarkers have been tested in active surveillance, and none have really panned out. This is still a relatively small study, but it’s incredibly promising and would be really great news for the field if the data holds,” Morgan told Medscape Medical News.

Morgan and his colleagues from nine institutions — three academic and six community centers — participated in evaluating the urine test. The primary endpoint was the detection of Grade Group 3 cancer or higher.

In the study, 223 men on active surveillance for low-risk prostate cancer provided a urine sample just before their scheduled surveillance biopsy. All patients underwent an initial MRI to look for any suspicious lesions. Each man then underwent a standard biopsy, and if the MRI showed a concerning lesion, additional targeted biopsies were taken from those areas.

Tosoian said the MPS2-AS test outperformed both MRIs and risk calculators — tools commonly used now to screen men on surveillance.

If the MRI Prostate Imaging Reporting and Data System alone was used, 48% of unnecessary biopsies would have been avoided while detecting 79% of cancers scored at Grade Group 3 and above, Tosoian said. If a Prostate Cancer Prevention Trial Prostate Cancer Risk Calculator alone was used, 16% of unnecessary biopsies would be avoided while 95% of cancers with Grade Group 3 and above would be identified.

The focus on predicting a patient’s risk for progressing to the critical Grade Group 3 and above reflects the threshold at which treatment is consistently recommended. In contrast, a proportion of men with Grade Group 2 cancers remain eligible for active surveillance, Tosoian said. The new study was designed to evaluate whether the urine-based test can predict when a cancer has progressed to a level that routinely warrants clinical intervention, he said.

Bradley Moore, MPH, spokesman for Lynx Dx, said MPS2-AS, like MPS2, supports both in-office and at-home urine collection and does not require cold shipping.

Christian Pavlovich, MD, director of the Prostate Cancer Active Surveillance Program at Johns Hopkins in Baltimore, said, “MPS2-AS might be the biomarker we have been looking for. While not all GG2 is indolent and any pattern 4 is potentially dangerous, there is certainly benefit to a urinary test that can help decide if and when surveillance MRI and biopsy are needed. So let’s hope MPS2-AS ushers in a new era of molecular prognostication for patients living with untreated prostate cancer. Of course, we will have to see the data in full before getting too excited, but this abstract certainly suggests there is much to be gained by using this test.”

Michael Leapman, MD, clinical program leader at the Prostate & Urologic Cancers Program at Yale Cancer Center, in New Haven, Connecticut, called the new study “impressive and thoughtfully executed.”

But he added, “MRI-positive rates were high, and the prevalence of upgrading in this cohort suggests the possibility of enriched risk. As such, a prospective, randomized trial would be important to isolate the true incremental benefit of MPS2 testing and to understand how it performs.”

Tosoian reported being an advisor to and a co-founder of Lynx Dx. Leapman has been listed as an uncompensated researcher with Veracyte, Inc., a company involved in other genomic and molecular diagnostic platforms. Morgan reported no relevant financial conflicts of interest.

Howard Wolinsky is a Chicago-based freelancer who has been on active surveillance for 15 years and writes the Substack newsletter, TheActiveSurveillor.com.