A new prostate cancer test that relies on measuring levels of a blood protein called EPCA-2 accurately found cancer 94 percent of the time, a significant improvement over the current PSA test, according to a study released Wednesday.
Each year, about 1.6 million men undergo biopsies because they test positive on a PSA (prostate-specific antigen) test – but only about 230,000 of them have cancer.
The new EPCA-2 test not only detected prostate cancer, but also could determine if it had spread to other parts of the body, according to the study published in the journal Urology.
“It could allow us to help patients decide if they need a biopsy or if it’s tame or has the ability to invade outside the prostate,” said Robert Getzenberg, director of research at James Buchanan Brady Urological Institute at Johns Hopkins University and a co-author of the study.
The test still faces large-scale clinical trials and review by the U.S. Food and Drug Administration, but it could be available in early 2008, said Getzenberg, who is a consultant to Seattle-based Onconome Inc., which is developing the test technology.
Prostate cancer is the second most frequently diagnosed cancer in men, after skin cancer, and the second leading cause of cancer death in men, after lung cancer, according to the American Cancer Society. Each year, about 230,000 new cases are diagnosed and about 27,000 men die, according to ACS.
Rectal examination and the PSA test, which was approved in 1994, have been the primary methods of detecting the cancer. But questions about the accuracy of the PSA test have been building over the years. It has a high level of false positives, often requiring biopsies, and misses about 15 percent of prostate cancers.
Another problem is that the PSA test does not distinguish between the cancer’s aggressive form, which is frequently fatal, and a slow-growing form that patients safely can live with.
The researchers measured the EPCA-2 levels in the blood of 385 men who were known to have cancer or were free of it.
Men who had an elevated EPCA-2 test had cancer 94 percent of the time, compared with about 19 percent of men with an elevated PSA result, reported in previous studies.
The test falsely sounded an alarm 3 percent of the time.
