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Testosterone replacement therapy has become a more than $400 million-a-year business in the United States, up from $18 million in 1988 and still rising. Because of increased advertising in magazines, on TV and elsewhere, more and more patients are asking about it. But is testosterone replacement therapy safe or a repeat of the estrogen replacement therapy fiasco?
A two-hour seminar explored that question and gave Assembly attendees advice on which patients to treat with TRT. The seminar leader was Douglas Kamerow, M.D., M.P.H., clinical professor of family medicine at Georgetown University and chief scientist with Research Triangle Institute (RTI) International, Washington, D.C.
Whom to treat
"Hypogonadal men should be on testosterone replacement therapy, no question about it," Kamerow said. But for others, there are no clear answers.
"For men with symptoms and low to low-normal testosterone levels, cautious use of testosterone replacement on a trial basis is a reasonable strategy at this time, while monitoring for side effects and adverse reactions," he added.
Monitoring of men who are on TRT should include blood tests for serum testosterone levels, hemoglobin, prostate-specific antigen and lipids, and liver function tests, he said.
An estimated 4 million to 5 million men in America are hypogonadal, Kamerow noted, but only about 5 percent of them receive testosterone therapy. The FDA has listed primary or secondary hypogonadism caused by surgery, radiation therapy, infections or genetic disorders as the main indications for TRT.
Clinicians can diagnose hypogonadism if the patient's total testosterone level is approximately 200 ng/dL, "although others use 300 to 350 ng/dL as the cutoff," he said.
Normal levels of testosterone may range from 300 to 1,000 ng/dL. They peak in men at age 17 and decline gradually over time, falling about 1 percent per year for men in their 30s and 40s -- making diagnosing older men difficult.
Treat symptoms
"Treat symptoms, not levels," Kamerow advised. For men who are not clearly hypogonadal, symptoms can include low sex drive and declining muscle mass and fat-free body mass. Studies have shown that replacement therapy probably does improve libido, especially for men with low testosterone levels at baseline, but not erectile dysfunction. It also has been shown to increase muscle mass and lean body mass.
"There are now easy-to-use, effective testosterone products available," he said. Until recently, only intramuscular injections were on the market, but now the choices include patches, gels and buccal tablets. Each has its own pros and cons for patient use, but all are effective, he said.
Kamerow was part of a group that reviewed studies of the effects of TRT for the Institute of Medicine. The studies found no direct evidence of increased prostate cancer rates in men who take TRT, although PSA levels may rise.
There is also no direct evidence of increases in coronary artery disease, although effects on lipid levels have been mixed -- lipids have worsened in some men and improved in others, he said.
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Copyright © 2004 by American Academy of Family Physicians.