Researchers from the University of California at San Diego have reported observations on 20 men who developed prostate cancer after receiving testosterone treatment for sexual dysfunction or “rejuvenation.” The details of this report appeared in the August 2005 issue of the Journal of Urology .[1]

Testosterone therapy products have been approved by the U.S. Food and Drug Administration for treating a limited number of conditions, particularly hypogonadism associated with low testosterone levels. Hypogonadism occurs in men of various ages, and most clinical studies of the therapy so far have been in younger men. Recent studies have shown that a significant percentage of otherwise healthy older men have testosterone levels consistent with hypogonadism. Data also suggests that low testosterone in elderly men is associated with a loss of lean body mass and muscle strength and increased central body fat. There may also be decreased bone density and mental dysfunction associated with low testosterone levels. For these reasons an increasing number of elderly men are being treated with exogenous testosterone. However, the risks of administering testosterone to elderly men have yet to be defined.

In November 2003 the Institute of Medicine of the National Academies published a report on the status of exogenous testosterone therapy in elderly men.[2] This report supported performing a large-scale clinical study of testosterone therapy to treat age-related conditions in men 65 and older. The expert committee recommended going forward with trials involving a limited group of participants. They suggested that initial studies should focus on determining the efficacy of testosterone therapy in older men and the nature and extent of the potential benefits. A large-scale trial to determine long-term risks and effectiveness should be undertaken only if clinically significant benefits are demonstrated in the initial, shorter studies. They suggested that these studies should involve only older men who have been diagnosed with low testosterone levels and at least one symptom that might be remedied by the therapy and who are not at high risk for developing prostate cancer. The status of these studies two years later is not clear.

The authors of the present study reviewed the medical records of six urology practices and identified men who were undergoing testosterone therapy for sexual dysfunction or “rejuvenation” and had a subsequent diagnosis of prostate cancer. They identified 20 men who fit these criteria.  Prostate cancer was diagnosed in more than half the patients within two years of starting testosterone and the latest occurred eight years after initiating therapy. The tumors were described as moderate to high-grade. The median PSA at diagnosis was 5.1 ng/ml and the highest was 329 ng/ml. They reported that digital rectal examination was more sensitive than PSA assays for detecting cancer. They also observed that patients treated by non-urologists were monitored less frequently than those treated by urologists. The authors suggest more frequent monitoring of testosterone treated men.

Comments: This was not a population study, which makes it unclear whether or not these 20 patients represented an increased risk of prostate cancer due to exogenous testosterone. However, the possibility or probability that testosterone may increase prostate cancer incidence in the elderly has dampened some of the enthusiasm for using testosterone for “rejuvenation.”  Before testosterone is more widely used in the elderly it will be crucial to obtain the results of clinical trials suggested by the Institute of Medicine report.

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