No link found between testosterone replacement therapy, prostate cancer risk

San Francisco-Testosterone replacement therapy (TRT) in hypogonadal men does not appear to increase the risk for prostate cancer, according to an evaluation of 224 men with an indication for prostate biopsy, providing further evidence that TRT need not be avoided in this patient group.

The proportion of men on TRT in the study who had prostate cancer on biopsy was not significantly different from patients who did not receive TRT, reported first author Aksam Yassin, MD, PhD, chairman of the Segeberger Kliniken Institute of Urology and Andrology, Norderstedt-Hamburg, Germany.

Further, hypogonadism was not found to offer protection against prostate cancer.

Uncertainty over the safety of TRT, particularly the risk of prostate cancer in older men, hampers the use of TRT in hypogonadal men. Testosterone avoidance is based on the theory that aggressive prostate cancer requires medical or surgical castration to reduce the testosterone level, after which tumor regression is observed.

“We’ve experienced a paradigm shift in the last decade that testosterone treatment does not cause or increase the incidence of prostate cancer,” said Dr. Yassin, who presented the findings at the Genitourinary Cancers Symposium in San Francisco.

Dr. Yassin and colleagues evaluated whether testosterone deficiency, TRT, or 5-alpha-reductase inhibitor (5-ARI) therapy affect the risk of prostate cancer by analyzing testosterone manipulation in two subgroups: hypogonadal men receiving TRT and men with lower urinary tract symptoms with a prostate size >40 cm³ who were administered a 5-ARI as therapy.

Data were collected from 224 men who had an indication for prostate biopsy: either a serum PSA level >4.0 ng/mL, a PSA velocity ≥0.75/yr, hypogonadism (total testosterone level <3.5 µg/mL) with a serum PSA level ≥1.5 ng/mL, a positive digital rectal examination, or a positive finding on transrectal ultrasonography (TRUS). All underwent a TRUS-guided prostate biopsy from 12 to 14 cores.

Seventy-one (31.7%) of the 224 patients had prostate cancer detected. Prostate cancer incidence was 33.3% (43 of 129) in patients with PSA >4.0 ng/mL, 33.8% (48 of 142) in men with a PSA velocity ≥0.75/yr, 54.3% (25 of 46) among those with a positive digital rectal exam, and 34.6% (47 of 136) among those with a positive TRUS finding.

In addition, 44.7% (30 of 67) of those with hypogonadism and a PSA level ≥1.5 ng/mL had prostate cancer, “meaning that hypogonadism offers no protection against prostate cancer,” said Dr. Yassin. In looking at Gleason score and tumor stage, “Patients with lower testosterone values had higher staging and higher Gleason scores,” he said.

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Rates of PCa similar regardless of TRT use

Twenty-five percent (three of 12) of the men on TRT were found to have prostate cancer via biopsy, which was not significantly different (p=.757) from the 32.1% (68 of 212) not receiving TRT who were found to have prostate cancer.

“There is no compelling evidence for testosterone causing cancer, but we still have the contraindication for TRT in active prostate cancer. We need further research in this area. The dilemma is the need for large studies-at least 10,000 patients with symptomatic hypogonadism treated with TRT or placebo for at least 12 years and 9 months-to confirm the finding. Is that ethical? I don’t know,” Dr. Yassin said.

Some 22.4% (17 of 76) of patients on 5-ARI therapy had prostate cancer, compared with 36.5% (54 of 148) who did not receive 5-ARI therapy. The lower prostate cancer incidence among men on 5-ARI therapy is consistent with the large Prostate Cancer Prevention Trial and Reduction by Dutasteride of Prostate Cancer Events studies, Dr. Yassin noted.

There was no significant statistical difference in Gleason grades among patients who were on TRT, not on TRT, on 5-ARI therapy, or not on 5-ARI therapy (p=.573).

Dr. Yassin has received honoraria and research funding from Bayer and Ferring Pharmaceuticals, research funding from Ferring, and other remuneration from Teva Pharmaceuticals.UT

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