New Blood Test for Prostate Cancer Showing Promise

A new blood test, called EPCA-2, is showing potential as a screening blood test for prostate cancer. It is hoped that the EPCA-2 test will be more accurate than the current test, PSA, and detect more cancers with fewer negative biopsies. While screening for prostate-specific antigen (PSA) has been the standard of care for more than 2 decades, it is not specific for prostate cancer, and raised concentrations have been linked to other prostate conditions such as benign prostatic hyperplasia and prostatitis. Several groups have been working to identify new biomarkers for prostate cancer, and this latest effort, published in the April issue of Urology, shows that EPCA-2 has potential as a new serum-based test.

Due to elevated PSA levels, an estimated 1.6 million men undergo prostatic biopsies in the United States every year. Approximately 60% of these patients have negative results, reports a news release about the study. Conversely, about 15% of men with prostate cancer go undetected because their PSA levels are below the cutoff level. The most recent study showed negative results in normal men 92% of the time, meaning that few men without cancer would have an elevated test and undergo biopsy. The study also found that 94% of men with cancer had an elevated test and would be biopsied, and few men with cancer would be missed by the test.

EPCA-2 is the second prostate-cancer marker identified by the same researchers that has outperformed PSA. Last year, the team identified a tissue-based test, EPCA-1, that also proved effective in flagging prostate cancer. The only similarity between these markers is that they were discovered using the same approach. The efficacy of EPCA-1 as a test of biopsy samples is currently being studied.

“A blood test based on EPCA-2 may greatly improve our ability to accurately detect prostate cancer early, minimize the number of false positives, and lower the number of unnecessary biopsies,“ senior author Robert Getzenberg, PhD, from the Brady Urological Institute at Johns Hopkins Hospital, in Baltimore, Maryland, told reporters. “In addition, this is the first time we have a test that effectively distinguishes between men with cancer confined to the prostate and those whose disease has spread outside the gland.“

The investigators report, “The results of our study have shown that EPCA-2 is a novel biomarker associated with prostate cancer that has high sensitivity and specificity and accurately differentiates between men with organ-confined and non–organ-confined disease.“ Dr. Getzenberg says larger clinical trials for EPCA-2 are planned that could make this test available in about 18 months.