Researchers in the United States say that prostate cancer developed in 20 men within months to a few years after they began testosterone supplementation, to correct a deficiency of the hormone.
Dr. Franklin D. Gaylis from the University of California at San Diego Medical Center, says that there are several anecdotal case reports, small studies, and observational studies such as theirs, that raise concern but do not as yet, provide conclusive evidence.
Gaylis, and colleagues say that in this series of patients where clinically significant prostate cancer developed, it was presumably related to testosterone use, and the issue is a concern because prostate cancer is usually driven by testosterone.
According to the researchers the men in the study were identified in six different urology practices.
It was found that prostate cancer was detected within 2 years of the start of testosterone replacement in 11 of these men, seven of them within the first year.
The others were diagnosed after 28 months to 8 years.
Before testosterone supplementation was begun, eleven of the men had normal prostate examination results.
According to the report the average PSA level of the 17 men tested before treatment was 3, although the range was 0.9 to 15.
Further evaluation is usually carried out if the PSA level is over 4.
The investigators therefore concluded that men, especially those with a family history of prostate cancer, should not receive a prescription for testosterone supplementation without careful, informed consultation regarding the risks and benefits of such treatment.
Gaylis says he hopes that guidelines will be developed by experts in the field, to help the appropriate and careful prescribing and monitoring of testosterone replacement, to men who need it, and who would benefit from it.
Dr. E. Darracott Vaughan, Jr. from Weill Medical College of Cornell University, New York, in a related editorial, says that it "can be taken as a 'shot across the bow' for urologists and other physicians, that they need to be extremely careful before beginning testosterone therapy.
The study is published in the Journal of Urology, August 2005.