Men’s Health Week 2018: Blood test detecting high-grade prostate cancers may bypass nearly half of all biopsies

By Liz Meszaros, MDLinx
Published June 11, 2018

Key Takeaways

A new blood test—IsoPSA—may avoid almost 50% of all prostate biopsies, and has been shown to be more accurate in predicting overall risk of prostate cancer than standard prostate-specific antigen (PSA) testing, according to study results presented at the 13th Annual Meeting of the American Urological Association held in May in San Francisco, CA.

“To be clinically useful, a biomarker must be both tissue-specific and cancer-specific. While PSA is prostate-specific, it is not specific for prostate cancer, leading to diagnostic inaccuracy and too many unneeded biopsies,” said Eric Klein, MD, chair, Glickman Urological & Kidney Institute, Cleveland Clinic, Cleveland, OH.

The new test could reduce the likelihood of overdetection and overtreatment of nonlethal prostate cancer.

Researchers conducted this multicenter validation study as a follow-up to earlier studies showing that IsoPSA, a structure-focused protein biomarker, may be effective in discriminating between high-grade prostate cancer of Gleason score ≥ 7 and low-grade or benign disease with a Gleason score of 6. They assessed the performance data of IsoPSA in a new cohort, using cutoffs derived from a preliminary study, with cancer detection via biopsy as the endpoint.

Dr. Klein and colleagues included 261 patients in their preliminary trial and 123 in their validation trial and obtained plasma samples within 30 days before prostate biopsies from patients with serum PSA levels from 2-62.8 ng/mL. They assessed results with IsoPSA against 12 core transrectal ultrasound guided (TRUS) biopsy results. In the preliminary study, 33.7% had high-grade prostate cancer and in the validation trial, 32.6%.

Upon ROC analysis of the preliminary vs validation study results, researchers found an AUC of 0.81 vs 0.82, respectively. Using the cutoff value established in the preliminary study (KR-HG risk probability < 17), the validation study showed a negative predictive value of 93.3%, compared with 94% in the preliminary study.

Clinically, 45.1% of the biopsies targeting high-grade disease could have been avoided in the preliminary study, as could 47.0% in the validation study.

“IsoPSA fulfills both the tissue- and cancer-specificity needed for a useful biomarker, and this validation study shows that it can more accurately detect high-grade cancer and reduce the rate of unneeded biopsies in patients at low risk of this disease,” concluded Dr. Klein.

Bringing men’s health to the forefront

This test and other advances in men’s health will be celebrated during Men’s Health Week, which is held annually in the United States in the week leading up to and including Father’s Day. This year, Men’s Health Week will take place from June 11-17.

Recognized by the White House, Men’s Health Week encourages men, boys, and their families to be more aware of preventable health problems and recommends early detection and treatment of disease among men and boys.

This week gives health-care providers, public policy makers, the media, and individuals the opportunity to encourage men and boys to seek regular medical advice and early treatment for disease and injury. Throughout the country, hundreds of awareness activities are planned.

For general information about Men’s Health Week, contact info@menshealthweek.org, or go to Men’s Health Network.

This study was funded by Cleveland Diagnostics, a company co-founded by the Cleveland Clinic, which developed the IsoPSA test.

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