More Evidence Of Link Between High Testosterone Levels And Prostate Cancer

7 June 2004
More Evidence Of Link Between High Testosterone Levels And Prostate Cancer
by George Atkinson

Men over 50 years of age with high blood levels of testosterone have an increased risk of prostate cancer, says a new study by researchers at Johns Hopkins. The finding casts some doubt on the safety of testosterone replacement therapy, the investigators say.

The researchers measured levels of testosterone in almost 3,000 blood samples collected over a 40-year period from 759 men, of whom 111 were diagnosed with prostate cancer. One form of testosterone, called free testosterone, which is biologically active and can be used by the prostate, was found to be associated with increased prostate cancer risk, according to J. Kellogg Parsons, the lead researcher at Johns Hopkins.

"Since testosterone replacement therapy increases the amount of free testosterone in the blood, older men considering or receiving testosterone replacement should be counseled as to the association until data from long-term clinical trials becomes available," says Parsons.

The association between free testosterone and prostate cancer risk in older men was not affected by height, weight, percent of body fat, or muscle mass. Total testosterone levels and dehydroepiandrosterone sulfate (DHEAS), another androgenic hormone, were also unrelated to prostate cancer risk, while the protein that binds testosterone in blood, called sex hormone-binding globulin (SHBG), was associated with a slightly decreased risk for prostate cancer.