The researchers found that EPCA levels were high in 11 of 12 prostate cancer patients (92 percent) and low in all of the healthy individuals. Only two bladder cancer patients and none of the other patients had elevated EPCA levels, suggesting that for this study, the test was correct 94 percent of the time. For comparison, only one-quarter of patients who undergo biopsies because they have elevated PSA values are actually positive for prostate cancer, while as many as 15 percent of those with low PSA values were found to have prostate cancer as detected by biopsy, according to Getzenberg.
Larger clinical trials are under way to further refine the EPCA test, to make it more sensitive so it can pick up even the smallest traces of the marker, and to verify its usefulness for detecting prostate cancer in a larger sample of patients, said Getzenberg.
Prostate cancer is the most common type of cancer found in American men. The American Cancer Society estimates that there will be approximately 232,090 new cases of prostate cancer in the United States in 2005, and 30,350 men will die of this disease.
Funding for the study was provided by Tessera Inc. Other authors on the report are Barbara Paul, Rajiv Dhir, Douglas Landsittel and Moira Hitchens, all of the University of Pittsburgh.