Croix Bleue du Québec

EPCA test may spot tumours five years before they are detectable in a biopsy

An experimental test may reveal hidden prostate cancer even when biopsy results are negative, potentially saving men from having repeated samples taken of their prostate tissue.

In a prostate biopsy, a small sample of prostate tissue is removed with a needle and examined under a microscope. The needle is inserted through the rectum, the urethra, or the area between the anus and scrotum.

The procedure is most often done when a blood test shows a high level of prostate-specific antigen (PSA), a protein made in the prostate gland and produced in larger amounts in most men with prostate cancer.

But some men with high PSA levels have negative biopsy results. If the high PSA levels persist, the men may have to undergo repeat biopsies.

The test looks for a protein called EPCA, which is present throughout the prostate gland during the earliest stages in the development of cancer but absent in normal tissue.

In a preliminary study of the test, Robert Getzenberg and colleagues examined 29 prostate tissue samples from men with prostate cancer who had initial negative biopsies and 27 prostate tissue samples from healthy men.

EPCA was present in almost all the negative biopsies from men subsequently found to have prostate cancer and, significantly, the test identified prostate cancer five or more years prior to it being diagnosed by biopsy in these cases. The protein was not found in the prostate samples from healthy men.

"By testing for EPCA in men with high levels of PSA, we may be able to detect the presence of prostate cancer earlier, before it is discoverable by biopsy, saving patients the fear and stress of repeat procedures and enabling us to treat the disease sooner," Getzenberg says in a news release.

The study was funded by Tessera Diagnostics, a biotechnology company in Seattle.

©The Medical Posting 2004