Long-term data show no link between TRT, prostate Ca

Orlando, FL-Prospective, long-term follow-up in a large cohort of hypogonadal men treated with testosterone replacement therapy (TRT) provides no evidence that TRT increases the risk for prostate cancer.

As reported by first author Ahmad Haider, MD, at the AUA annual meeting in Orlando, FL, 5 of 300 men developed prostate cancer (incidence, 1.7%; 39.4 per 10,000 patient years) during 6 years of TRT with parenteral testosterone undecanoate (AVEED). The men were in their 50s and 60s at TRT initiation, and prostate cancer was diagnosed after rising PSA prompted a biopsy. The cancer was identified at 10 to 11 months after TRT initiation in three men and after about 1.5 years in the other two patients. All men had low Gleason grade tumors, were treated by radical prostatectomy, and had ≤pT2a disease.

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“The incidence of prostate cancer per 10,000 patient years was 116 in the Prostate, Lung, Colorectal, and Ovarian Cancer screening (PLCO) study and 96.6 in the European Randomized Study of Screening for Prostate Cancer (ERSPC),” said Dr. Haider, who is in private practice in Bremerhaven, Germany.

Ca incidence ‘lower than might be expected’

“Although we cannot directly compare our data to these large screening studies, the incidence of cancer in our cohort of men was much lower than might be expected in the general population, and so it does not suggest that long-term TRT for treatment of hypogonadism increases the risk of prostate cancer.”

Abdulmaged Traish, PhD, MBA, was a co-author of the study. Speaking to Urology Times, he said, “Based on knowledge that testosterone can stimulate existing prostate cancer, there has been ongoing concern about the safety of TRT. To my knowledge, there is no evidence that testosterone is a carcinogen that can induce cancer in normal prostate tissue, but if it were true, we would have seen a higher incidence of prostate cancer in this patient population.

Next: “The critical message of our study is that testosterone therapy in itself does not cause prostate cancer."

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Dr. Traish“Instead, the incidence was less than half that reported in the large screening trials. Although data from an observational study can be criticized as weak, without observational studies we would have no information on this topic,” said Dr. Traish, professor of urology and biochemistry at Boston University School of Medicine, Boston.

“The critical message of our study is that testosterone therapy in itself does not cause prostate cancer, and this is consistent with evidence from data from large studies finding no associations between serum testosterone and prostate cancer and groups reporting on the safety of using TRT in hypogonadal men who underwent radical prostatectomy for localized disease.”

At baseline, the 300 patients in the study had a mean age of 58 years and a testosterone level of ≤12 nmol/L (3.5 ng/mL). They were treated with testosterone undecanoate, 1,000 mg at baseline, 6 weeks, and every 12 weeks thereafter. There were no dropouts from the study; almost all men were seen at 1 year and nearly half had completed 5 years of follow-up, and so far, 87 men reached the 6-year visit.

Mean testosterone rose from 9.86 nmol/L at baseline to a trough level in the range of 16 to 17 nmol/L throughout follow-up. Data on other parameters assessed at regular follow-up visits showed that mean prostate volume increased by 2.96 mL (<10%).

“The change was statistically significant, but the effect of the treatment was not dramatic. Rather, TRT increased the smallish prostates in these hypogonadal men to a more normal size,” Dr. Traish said.

Decline in mean IPSS observed

Mean PSA rose from 1.77 ng/mL at baseline to 2.0 ng/mL. Mean International Prostate Symptom Score (IPSS) was 6.57 at baseline, decreased significantly at 1 year, and continued to decline with a mean change of –4.83 at 6 years. The same pattern was observed for change in residual post-voiding urine volume, which decreased from 46.79 mL at baseline to 15.85 mL at 6 years.

“IPSS was 19 at baseline in the patient with the most severe symptoms, and it decreased to 3 at last follow-up,” Dr. Haider said.

Mean International Index of Erectile Function-Erectile Function domain improved significantly after 12 months of TRT and reached a plateau at 36 months; the mean baseline score was 20.01 and the mean change was +5.37.

The majority of patients were overweight or obese when starting TRT. At 72 months, mean body weight had decreased by 16.8 kg from baseline and mean waist circumference by almost 9 cm.

“Some of the benefits associated with TRT observed in these patients may be a result of a parallel reduction in body weight, visceral fat, and other elements of the metabolic syndrome, including improvements in lipid pattern, blood pressure, and glucose homeostasis,” Dr. Haider said.

Bayer Pharma AG partially supported the study. Dr. Haider is a meeting participant/lecturer for Bayer Pharma AG, Jenapharm, and Takeda Pharmaceutical Co. Co-author Gheorghe Doros, PhD, has a relationship with Bayer Pharma AG.UT

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