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U.VA. RESEARCHERS DEVELOP NEW TEST FOR RESIDUAL PROSTATE CANCER

For men who have surgery to remove a cancerous prostate gland, a big fear is that the surgeon's knife may leave behind undetected cancer around the margins of the surgery. But there's hope in a new test developed by researchers at the University of Virginia for improved detection of residual cancer after surgery.

Results of a pilot study on the new procedure were published as the lead article in the May 1999 issue of The Journal of Urology. Dr. Dan Theodorescu, who also holds the Paul Mellon Chair in Urologic Oncology, co-authored the article with Dr. Henry F. Frierson, Jr., professor of pathology, and Robert A. Sikes, assistant professor of urology at U.Va. The study compared the new testing technique with current methods using 30 patients who were having radical prostatectomies.

We developed a new molecular method to figure out how extensive the cancer is, Theodorescu said. When you surgically remove the prostate containing the cancer, the pathologists look at the edges of the surgical area to figure out whether the cancer is present at the edge of the specimen. If it is, then that patient has what we call a positive margin. But that method doesn't allow you to determine if there is prostate tissue left behind in the patient.

Instead, the U.Va. team used molecular biological techniques to test the tissue surrounding the surgery site. This test is a more refined and far-reaching version of the test normally used to screen for higher prostate-specific antigen (PSA) levels in the blood. It is a very sensitive molecular assay that analyzes tissues left inside the patient instead of analyzing additional surgically removed tissue, Theodorescu said.

The new test may also be quicker and less costly than the current practice of margin tumor assessment. Not only were we able to pick up all the cancers that the traditional method of microscopic examination was able to detect, but in 20 percent of the patients, we also found positive areas not detected by conventional methods, Theodorescu said.

Theodorescu is continuing to follow these patients to find out the rate of cancer recurrence. If the new molecular test continues to prove so highly reliable in larger clinical trials, it may be useful for finding residual cancers around other organs that are commonly treated by surgery, such as the colon, ovary and bladder, he said.

September 29, 1999