Testosterone Replacement in Older Men Does Not Increase Risk of Prostate Cancer

Older men who receive testosterone replacement therapy because of low testosterone are no more likely to get prostate cancer than similarly aged men not receiving testosterone, a new study found. The results will be presented at The Endocrine Society’s 90th Annual Meeting in San Francisco.

Prostate cancer is a concern regarding testosterone therapy in older men, said lead author Aksam Yassin, MD, PhD, of the Clinic for Urology and Andrology of the Segeberger Clinics in Norderstedt, Germany. “Testosterone treatment stimulates the growth of an existing prostate cancer, but there is no evidence that it causes this type of cancer,” he said.

The risk of prostate cancer and testosterone deficiency increases with age. Therefore, it is possible that a prostate cancer may occur in an older man during testosterone replacement therapy, which is unrelated to treatment, Yassin said. His research, performed with scientists from Germany and the United Arab Emirates, aimed to determine if prostate cancer occurs more often with testosterone replacement therapy in men over 50.

The study involved 154 testosterone-deficient men with an average age of 56, who had 1 to 3 years of follow-up testing. Patients received testosterone injections in a hospital clinic in Bremerhaven, Germany. Testosterone was a slow-release form called testosterone undecanoate (brand name Nebido) that is not yet available in the United States. The researchers compared these patients with 160 men visiting the clinic for a health checkup who had normal testosterone levels and did not receive testosterone treatment. Their average age was 58.

At the beginning of the study and then every 3 months afterward, all subjects had an evaluation that included a digital rectal exam, ultrasound measurement of prostate volume and a blood test for prostate-specific antigen (PSA). Increased PSA levels may indicate prostate cancer, an enlarged prostate or inflammation of the prostate (prostatitis). If a man’s PSA level was high—over 4 (micrograms per liter)—or otherwise abnormal, he underwent a prostate biopsy.

The rectal exam found no abnormalities. Eleven men receiving testosterone had a biopsy, two of which showed a small cancerous tumor on one side of the prostate. A third man was found to have a high-grade (more aggressively malignant) prostate cancer that had not yet spread to other organs. Of the 12 men in the untreated group, five had prostate cancer. Four of these tumors were on both sides of the prostate and were high grade. Therefore, there were no more prostate cancers in the group that received testosterone treatment, Yassin concluded. Moreover, the men receiving testosterone had smaller, less aggressive tumors than did the other men, he said.

“There is increasing evidence that testosterone replacement therapy in testosterone-deficient men can improve their symptoms, such as decreased bone and muscle mass and low sex drive and depression,” he said. “In view of the many benefits of treatment and the results of our study, we believe it is acceptably safe to treat older men with testosterone if there is a good reason for treatment.”