Testosterone Replacement Therapy: Is It Safe?
Researchers Worry That Testosterone Use Is Way Ahead of Evidence
Feb. 23, 2004 (Orlando) -- Just as American women once clamored for estrogen as a panacea for aging -- hoping to keep their hearts young and their minds sharp -- middle-aged men are looking at testosterone as a possible fountain of youth, sending testosterone sales through the roof and medical experts scrambling to avoid an estrogen-like disaster.
Douglas B. Kamerow, MD, MPH, chief scientist at RTI International in Washington, D.C., says testosterone is being marketed as a cure for "middle-aged blues, fatigue, or declining sexual desire," and men are clearly receptive to the sales pitch: Prescriptions for testosterone increased "170% from 1999 to 2002, and sales increased from $18 million in 1988 to $400 million in 2003."
The growth market in testosterone caught the attention of the National Institutes of Health, which is concerned about the potential for another "hormone disaster," Kamerow tells WebMD. He presented his testosterone study at the annual meeting of the American College of Preventive Medicine (ACPM).
Women used to be routinely put on hormone replacement therapy at menopause because observational studies suggested that menopausal women on HRT had lower rates of heart disease and stroke -- diseases that typically increase in postmenopausal women. Tens of thousands of women were prescribed hormone therapy without careful clinical studies to prove the therapy worked. When the NIH studied therapy with the hormones estrogen and progestin in healthy menopausal women, it discovered that the therapy could increase the risk for stroke, blood clots, and breast cancer without offering any protection for the heart. The results were so compelling that the NIH actually halted the study early.
The FDA says testosterone replacement should only be used to treat a condition called male hypogonadism, which means that the testes aren't producing sufficient amounts of testosterone. Kamerow says there are about 4 million to 5 million American men with this condition but only about 5% are receiving testosterone replacement therapy. "So clearly the bulk of prescriptions are for off-label use," he says.
"The concern is that we could have the same situation with testosterone, only the problem would be prostate cancer," Kamerow says. Testosterone increases levels of prostate specific antigen, or PSA. Increased levels of PSA are a marker for prostate cancer, although some PSA increases are caused by a noncancerous enlargement of the prostate, which is called benign prostatic hyperplasia.
The problem, says Kamerow, is that men -- especially middle-aged men -- are eager to try the hormone, which is hyped as a cure-all for everything from lack of strength to lack of libido. Advertising also suggests testosterone can cure the blues, says Kamerow. But when the Institute of Medicine asked him to find some evidence of this, he came up empty handed.
Kamerow and colleagues identified 48 publications describing the results of 39 testosterone studies, most of which were "poorly designed, with small sample size -- ranging from 6 to 108 men -- and brief duration. Only 31 of the trials were placebo-controlled," he says. Perhaps even more important: All the studies were in men who had testosterone injections. There are no studies of the newer -- and best-selling -- testosterone products: patches and gels. -->