A novel blood test was more accurate than PSA screening for identifying patients with high-risk prostate cancer, according to findings presented at the Annual Meeting of the American Urological Association.
IsoPSA, (Cleveland Diagnostics) — a blood- and structure-based assay — could reduce the necessity of biopsies for prostate cancer, thereby reducing overdetection and overtreatment of the disease, researchers reported.
“To be clinically useful, a biomarker must be both tissue specific and cancer specific,” Eric Klein, MD, chairman of the Glickman Urological & Kidney Institute at Cleveland Clinic, said in a press release. “While PSA is prostate specific, it is not specific for prostate cancer, leading to diagnostic inaccuracy and too many unneeded biopsies.”
Klein and colleagues performed a prospective validation of the IsoPSA assay, evaluating plasma samples from multiple centers in both preliminary (n = 261) and validation (n = 123) trials. Researchers collected all samples within 30 days before prostate biopsy from patients with PSA levels of 2 ng/ml to 62.8 ng/ml.
Klein and colleagues evaluated the assay against 12 biopsy results as the gold standard, with a subset of 10 MRI-guided biopsies in the preliminary cohort and 42 in the validation cohort. The prevalence of high-grade patients was 33.7% in the preliminary cohort and 32.6% in the validation cohort.
A receiver operating characteristic curve analysis showed an area under the curve of 0.81 in the preliminary group and 0.82 in the validation group.
Nearly half of biopsies in both the preliminary and validation studies could have been avoided with the novel assay (45.1% vs. 47%).
“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 [among] patients at low risk of this disease,” Klein said. – by Andy Polhamus
Klein E, et al. Abstract PD60-05. Presented at: Annual Meeting of the American Urological Association; May 18-21, 2018; San Francisco.
Disclosures: Cleveland Diagnostics, a company co-founded by Cleveland Clinic, developed IsoPSA and funded the study. Klein reports no relevant financial disclosures. One author is the chief medical officer of Cleveland Diagnostics and holds financial interest in the company.