Nov. 7--A research study, co-led by Wake Forest University School of Medicine, has found that a hormone normally occurring in the body may cause some elevated levels of prostate specific antigen in men.

Those elevated levels often lead to a recommendation for a prostate biopsy since they can be a potential sign of prostate cancer.

However, the researchers found that parathyroid hormone, a substance the body produces to regulate calcium in the blood, can elevate the antigen levels in healthy men.

These non-cancer elevations could cause many men to be biopsied unnecessarily, which often leads to unnecessary treatment and increased rate of side effects, including impotence and urinary incontinence.

"The problem is that, as men age, they often develop microscopic cancers in the prostate that are clinically insignificant," said Dr. Gary Schwartz, an associate professor of cancer biology and epidemiology and prevention at Wake medical school. "If it weren't for the biopsy, these clinically insignificant cancers, which would never develop into fatal prostate cancer, would never be seen."

Only in one of six cases does a biopsy diagnosis of prostate cancer result in a cancer that would be fatal if untreated, he said.

The finding is especially significant for black men, since 20 percent of black men have elevated parathyroid hormone levels compared with about 10 percent of white men.

The University of Wisconsin at Madison also participated in the study, which appears in the current issue of Cancer Epidemiology, Biomarkers & Prevention. The study was funded by grants from the National Institutes of Health and the American Cancer Society.

rcraver@wsjournal.com. -- 727-7376

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