Researchers say a new blood test for prostate cancer could greatly improve the accuracy of results.
The study, released by The Johns Hopkins School of Medicine, examined a newly discovered blood protein, ProstaMark (R) EPCA-2 (Early Prostate Cancer Antigen).
The researchers found that it is a more accurate indicator of whether a patient has prostate cancer than current blood tests are.
Under the current standard, blood tests measure prostate-specific antigen (PSA) to detect prostate cancer. However, the tests are not highly specific or sensitive.
For example, in the U.S., 80 per cent of patients with elevated PSA levels do not have prostate cancer and 15 per cent of patients with normal PSA levels do have prostate cancer.
As a result, based primarily on PSA test results, nearly 1.7 million prostate biopsies are performed annually in the U.S. and an estimated 25 million men have at least one negative biopsy.
The EPCA-2 test results have a much better accuracy rating. In the study, which looked at 330 patients, the tests were negative in 97 per cent of men who did not have the disease and positive in 94 per cent of men who do have the disease.
"In my opinion, this could be a revolutionary finding," professor Robert Getzenberg, the study's lead author, told the Toronto Star.
"The holy grail of prostate cancer is to find something that tells us whether you have a bad prostate cancer or a good one," says Getzenberg. "And I think we have the potential to have a marker that can do that."
EPCA-2 is a protein substance that is a key building block of the deformed nuclei that would show cancerous prostate cells. When these cells break down, EPCA-2 proteins are released into the bloodstream where they remain stable for long periods of time.
Onconome, Inc., a privately held Seattle biotechnology company, holds the exclusive worldwide rights to the technology and provided a grant for the research.
Getzenberg said the tests could be widely available within two years.
