Hormone may elevate PSA levels

A hormone found naturally in the body may elevate prostate-specific antigen levels in men, leading physicians to perform unnecessary biopsies, according to a study in the November issue of Cancer Epidemiology, Biomarkers & Prevention.

The study analyzed data from 1,273 men who participated in the National Health and Nutrition Examination Survey from 2005 to 2006 and did not have prostate cancer.

After adjusting for age, race and body mass index, the data indicated that higher concentrations of serum parathyroid hormone were associated with higher total and free-serum PSA concentrations.

Researchers found that many men older than 40 had elevated PTH levels of 66 pg/mL or greater. The prevalence of these elevated PTH levels was nearly twice as great among black men.

"We discovered a significant non-cancer elevation in PSA caused by PTH," said Gary G. Schwartz, PhD, MPH, author of the study and associate professor of cancer biology and epidemiology and prevention at Wake Forest University School of Medicine in North Carolina.

"It is possible that in determining whether a man is a candidate for biopsy, in addition to measuring PSA, doctors may measure PTH as well. And it may help in making PSA testing more specific for cancer," Schwartz said.

In many cases, he said, aging men develop microscopic cancers in the prostate that are clinically insignificant and likely would not develop into fatal prostate cancer. He estimates that 17% of diagnosed prostate cancer proves fatal.

Schwartz urged physicians to consider the way PTH influences a man's PSA levels -- particularly black men -- before scheduling a biopsy, which could lead to unnecessary treatment and possible side effects, including impotence and incontinence.

"If around 80% wouldn't die of their prostate to begin with, that's not a very good trade," he said.