Hypogonadal men who receive testosterone replacement therapy (TRT) may have a lower incidence of prostate cancer (PCa) than those not receiving TRT, according to study findings presented at the Sexual Medicine Society of North America 18th Annual Fall Scientific Meeting in San Antonio, Texas. In addition, PCa diagnosed in TRT recipients is less severe than PCa diagnosed in men unexposed to TRT.
Ahmad Haider, MD, in private urology practice in Bremerhaven, Germany, and colleagues studied 400 hypogonadal men (testosterone level of 350 ng/dL or less) who received testosterone undecanoate 1000 mg every 3 months for up to 10 years and 376 hypogonadal men who opted against TRT (control group). During a median follow-up of 8 years, 9 men in the TRT group (2.3%) were diagnosed with PCa compared with 26 (6.9%) in the control group. The incidence was 31 per 10,000 years in the TRT group compared with 95 per 10,000 years in the control group.
All men in the TRT group underwent radical prostatectomy (RP), and all but 1 patient had a Gleason score of 6 or less. All had a predominant Gleason score of 3 and all had a tumor grade of G2 and tumor stage T2. In the control group, 18 underwent RP alone, 6 underwent RP and radiation, and 2 had radiation alone. All 26 patients had a Gleason score above 6, and 2, 20, and 4 had a predominant Gleason score of 3, 4, and 5, respectively. Tumor grade was G2 in 6 patients (23%) and G3 in 20 (77%). One patient (4%) had tumor stage T2 and 25 had tumor stage T3.
“In the testosterone group, all prostate cancers were diagnosed within the first year and a half suggesting that cancers had been present prior to initiating testosterone therapy,” Dr Haider said. “Because low testosterone is associated with low PSA, hypogonadism may contribute to reduced detectability of prostate cancer. Normalizing testosterone may have brought out the occult cancer.”
He added: “Our registry is ongoing, and we keep following our patients year after year. The results are getting more robust with advancing time.”
The next update will be presented at the Genitourinary Cancers Symposium in San Francisco in February 2018.
The new findings add to those from previous studies showing a protective effect of TRT against PCa. Earlier this year, Stacy Loeb, MD, of New York University, and colleagues published the results of a case-control study in the Journal of Clinical Oncology (2017;35:1430-1436) showing that men who received TRT had a decreased risk of aggressive PCa. Using the National Prostate Cancer Register of Sweden, the investigators compared 38,570 patients with PCa and 192,838 age-matched men without PCa (controls). Of these, 284 patients with PCa (1%) and 1378 (1%) controls filled TRT prescriptions. In multivariable analysis, the investigators found no association between TRT and overall PCa risk. Patients who received TRT had a significant 35% increased odds of more favorable-risk PCa and 50% decreased odds of aggressive PCa compared with patients not exposed to TRT.
In a population-based matched cohort study of men aged 66 years or older in Ontario, Canada, Christopher J.D. Wallis, MD, PhD, and colleagues from the University of Toronto found that TRT recipients in the highest tertile of testosterone exposure had a significant 40% decreased risk of a PCa diagnosis compared with controls, according to a paper published in Lancet Diabetes Endocrinology (2016;4:498-506). The study included 10,311 men who received TRT and 28,029 controls. Median follow-up was 5.3 years in the TRT group and 5.1 years in the control group.
Further, in a study published in the Aging Male (2017;20:125-133), Aksam Yassin, MD, from the Institute of Urology and Andrology, Segeberger Kliniken, Norderstedt, Germany, and colleagues found that hypogonadal men who received TRT had a lower rate of PCa found on prostate biopsy compared with hypogonadal men not exposed to TRT and eugonadal men (16.7% vs 51.8% vs 37.8%, respectively). They also were less likely to have less severe PCa as determined by grading and staging.