A new urine test performed better than prostate specific antigen (PSA)-based testing and magnetic resonance imaging (MRI) for monitoring patients with low-risk prostate cancer on active surveillance. Use of the test to determine the need for repeat “monitoring” biopsies would have avoided up to 64% of unnecessary biopsies, while maintaining timely detection of higher-grade cancers that merit treatment, according to a study published by Tosoian et al in The Journal of Urology.
The test, called MyProstateScore 2.0 - Active Surveillance (MPS2-AS), was evaluated in over 300 patients on active surveillance for Grade Group (GG) 1 prostate cancer, according to lead author Jeffrey Tosoian, MD, MPH, Assistant Professor in the Department of Urology at Vanderbilt Health.
“For patients undergoing monitoring of low-grade prostate cancer, these findings suggest that use of the urine test can reduce the need for invasive biopsies without compromising prompt detection of higher-grade cancers that require treatment,” Dr. Tosoian explained.
Active surveillance is widely used in men with low-risk prostate cancer to avoid unnecessary treatment of cancers unlikely to cause harm. Because some patients will later be found to “upgrade” to higher-risk cancers, however, surveillance entails careful monitoring. Due to the limitations of existing tools, the current approach to surveillance requires repeat prostate biopsies, usually every 2 to 3 years. The urine test offers a noninvasive option to determine which patients truly need to undergo a biopsy and which can avoid a potentially unnecessary and invasive procedure.
Other noninvasive tests have been studied in active surveillance, but none have had sufficient accuracy to rule out the need for repeat biopsies. Dr. Tosoian said the research team is optimistic that these findings reflect a significant step forward for the field.
Prostate cancer grading uses the Gleason score (6–10) and Grade Group (1–5) systems to estimate cancer aggressiveness based on how the cells look under a microscope. Higher numbers indicate faster-growing, more aggressive cancer.
In patients previously diagnosed with low-grade cancers (Gleason score 6, Grade Group 1) pursuing active surveillance, MPS2-AS correctly predicted the presence of high-grade (GG ≥ 3) cancer in 97% of cases. The test was found to have a 99% negative predictive value for GG ≥ 3 upgrading, meaning that patients with a negative test had only a 1% chance of having GG ≥ 3 cancer detected on biopsy. For most patients, that is low enough to confidently forgo the biopsy altogether, Dr. Tosoian said.
Dr. Tosoian, who is also the Director of Translational Cancer Research in the Department of Urology at Vanderbilt, said the next steps for the collaborative research team will include studying the use of this testing approach to improve other aspects of prostate cancer care, such as detecting recurrence after treatment.
DISCLOSURE: The study was supported by the National Institutes of Health (grant U2CCA271854). For full disclosures of the study authors, visit auajournals.org.
