Urinary RNA Test Points To Aggressive Prostate Cancer

Urinary RNA Test Points To Aggressive Prostate Cancer
Measuring RNA expression of two prostate cancer markers identifies which prostate cancer patients have Gleason score 7 or above disease

Date: 22 May 2017
Author: By Lynda Williams, Senior medwireNews Reporter
Topic: Prostate Cancer / Translational Research

medwireNews: Urinary RNA testing could help identify which patients diagnosed with early-stage prostate cancer have aggressive disease, suggest study findings published in JAMA Oncology.

“The multiplex urinary RNA algorithm was developed and validated in cohorts of men presenting for initial prostate biopsy owing to elevated PSA [prostate-specific Antigen] or abnormal DRE [digital rectal examination] findings and therefore represents a strategy to refine biopsy decisions after PSA screening rather than replacing PSA testing”, explain the researchers.

The team measured the expression of two RNA markers of aggressive prostate cancer – PCA3 and TMPRSS2:ERG –in the urine after DRE to determine if this would improve the specificity of detection of tumours with a Gleason score of 7 or above compared with a PSA test alone.

For the initial developmental cohort of 516 men, aged 33–85 years, the team used a threshold of urinary PCA3 and TMPRSS2:ERG that preserved sensitivity for detection of aggressive prostate cancer at 95%. This improved the specificity for detection from 18% with PSA alone to 39% with the test.

Analysis of the second, validation cohort of 561 men, aged 27–86 years, confirmed that using the RNA test increased specificity significantly, from 17% to 33%, while maintaining sensitivity at 93%.

“Use of these tests to select men for initial biopsy after elevated PSA or abnormal DRE findings showed that 42% of men would have been safely excluded from undergoing unnecessary prostate biopsy, while high sensitivity for aggressive cancer was retained”, say Martin Sanda, from Emory University School of Medicine in Atlanta, Georgia, USA, and co-authors.

“These findings suggest that urinary RNA testing can mitigate harms of prostate screening while retaining the benefits of identifying aggressive cancers suitable for treatment.”

And cost analysis indicated that using the test to restrict biopsy use and target biopsy to high-risk men, rather than all patients with an abnormal PSA, would reduce the cost of both cancer detection and care, with the greatest potential savings among men aged 55–64 years.

But the researchers add: “Relative to [US Protective Services Task Force] recommendations (where men would undergo neither PSA testing nor consequent biopsy), urine RNA testing to select men for biopsy would reduce treatment costs for advanced disease, but these were offset by costs of biopsies and care for early-stage prostate cancer.”

Reference

Sanda MG, Feng Z, Howard DH, et al. Association between combined TMPRSS2:ERG and PCA3 RNA urinary testing and detection of aggressive prostate cancer. JAMA Oncol; Advance online publication 18 May 2017. doi:10.1001/jamaoncol.2017.0177