If you're a middle-aged man, should you consider testosterone-replacement therapy to relieve symptoms of "male menopause?" That's the question we explore in this important Special Report that reviews the risks and benefits of testosterone-replacement therapy.
As they age, men experience their own version of menopause. It's less dramatic than the changes women experience, when their ovaries stop producing estrogen. But a man's testosterone level does begin a slow, steady decline -- about 1% per year -- in his early 40s. In spite of the drop in testosterone, many older men still have normal levels of this hormone, and they experience few bothersome symptoms.
For some men, however, declining testosterone levels can be accompanied by a number of troubling symptoms, including reduced libido (sex drive), erectile dysfunction, loss of muscle mass, depression, and a diminished sense of well-being. When these symptoms are present and the man's testosterone level is low, the condition is called hypogonadism. Other common terms for this condition include andropause, androgen deficiency of the aging male, and "male menopause."
Although use of testosterone-replacement therapy may improve many of the symptoms produced by low testosterone levels, some question whether it could also increase the risk of prostate cancer. Results from several recent small, short-term studies failed to raise any red flags. But no one yet knows whether testosterone-replacement therapy is safe when used over many years.
While symptoms are often the primary factor in the decision to initiate treatment, they are not the only factor. Most doctors are reluctant to prescribe testosterone supplementation unless the man is experiencing symptoms and his blood test confirms a testosterone deficiency. Typically, a testosterone level of 300 ng/dL is considered to be at the lower limit of normal in a healthy man. Currently, however, there is no consensus on what level of testosterone should be used to define testosterone deficiency.
What About the Risks of Testosterone-Replacement Therapy?
Testosterone-replacement therapy can make some men more prone to sleep apnea (a nighttime breathing disorder that can strain the heart), and it may lead to an overproduction of red blood cells (potentially aggravating existing cardiovascular disease). Testosterone-replacement therapy also causes the testicles to shrink and may impair fertility.
During the early months of testosterone treatment, prostate size increases. Usually after this increase, however, the prostate gland is no larger than it was before the age-related drop in testosterone levels. As a result, this prostate enlargement typically doesn't cause the bothersome urinary symptoms associated with benign prostatic hyperplasia (BPH).
Prostate cancer is the main concern. Among men who have an existing prostate cancer, the concern is that testosterone replacement could make the disease progress faster. This concern is based, in part, on the fact that withdrawal of testosterone (castration) among men with advanced prostate cancer causes the cancer to regress. A similar concern -- that administering testosterone could promote tumor growth in men with prostate cancer -- is why most doctors will not prescribe testosterone-replacement therapy to men with a history of the disease.
It is not known whether testosterone-replacement therapy actually promotes the development of new prostate cancer. But several short-term studies have been encouraging in this regard. In a six-month study in the JJournal of the American Medical Association, testosterone-replacement therapy did not significantly increase hormone levels in the prostate, and signs of potential cancer development (changes in prostate tissue composition, gene expression, and indicators of cell proliferation) were not apparent.
A Cautionary Tale
In the absence of long-term safety data, however, not all doctors embrace testosterone-replacement therapy for men with diminished testosterone levels. The dramatic rise and fall of hormone- replacement therapy for women provides a cautionary tale.
At one time, hormone-replacement therapy was enthusiastically prescribed to millions of postmenopausal women because it relieved a range of bothersome symptoms associated with low estrogen levels, helped prevent osteoporosis, and was believed to avert heart disease.
But the much-anticipated results of a long-term study called the Women's Health Initiative brought a disturbing surprise: Women taking hormone-replacement therapy actually had higher risks of cardiovascular disease and breast cancer than those who did not use it.
Today, hormone-replacement therapy is recommended only for postmenopausal women who have significant symptoms, and they should use it for the shortest possible time. Until testosterone-replacement therapy is studied in a similar long-term trial, many doctors will be reluctant to prescribe it for an extended duration.
