Prostate test may improve cancer detection

In men with high PSA levels and negative biopsy results, a test for a protein may reveal undetected cancer, or confirm that the patient does not have the disease, according to report in The Journal of Urology.

A negative biopsy in an individual with increased serum PSA “raises an important clinical dilemma, namely what to do with the patient at this time,” investigators explain. Typically, these patients undergo repeat biopsies depending on subsequent PSA readings.

Using antibodies they developed against a protein, called EPCA, Dr. Robert Getzenberg from the University of Pittsburgh Cancer Institute and others stained 29 prostate tissue samples from patients with prostate cancer who had initial negative biopsies and 27 prostate tissue samples from healthy men.

The intensity of the EPCA staining in the samples analyzed from the patients with prostate cancer were significantly different compared to samples from the healthy subjects, “with almost no overlap in staining results,” the team reports.

Positive staining for EPCA was significantly associated with the presence of prostate cancer.

Increased EPCA expression was observed in nearly all of the negative biopsies from patients subsequently found to have prostate cancer.

Moreover, EPCA staining “identified prostate cancer 5 or more years prior to its being diagnosed pathologically in these cases,” Getzenberg told Reuters Health. By comparison, non-diseased prostate tissue showed “few instances” with increased EPCA expression.

“The EPCA marker can be used to stain prostate biopsies that do not have pathological evidence of prostate cancer and determine if the patient does or does not have the disease,” Getzenberg said. “This will save repeated biopsies in men that might have elevated PSA levels but do not have positive biopsies.”

A multicenter trial assessing the value of EPCA in prostate cancer is planned. A test for EPCA “could serve as an adjunct to the current diagnostic approach to a patient who undergoes prostate needle biopsy,” the investigators conclude. —Reuters

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