ASCO 2017: Prostate cancer in 696 hypogonadal men with and without long-term testosterone therapy: Results from a controlled registry study

Chicago, IL (UroToday.com) The endocrinology relationship between testosterone and prostate cancer (PCa) is well-established, however whether men with hypogonadism have increased prostate cancer incidence or severity is controversial. Dr. Ahmad Haider and colleagues from Germany presented their results of assessing prostate cancer outcomes among men on long-term testosterone therapy (TTh) at the 2017 ASCO annual meeting’s prostate cancer poster session.

A recent Canadian population-based observational study reported that men treated with testosterone replacement therapy were at decreased risk of prostate cancer diagnosis compared to controls.1 Thus, the objective of this study was to assess the incidence and severity of prostate cancer in hypogonadal men on long-term testosterone therapy in comparison to an untreated hypogonadal control group. 

For this study, 400 men with testosterone ≤350 ng/dL and symptoms received testosterone undecanoate 1000 mg replacement therapy every 3 months for up to 10 years, while 296 hypogonadal men (age 57-74) opted against replacement therapy and formed the control group. Prostate volume, PSA, weight and C-reactive protein (CRP) were assessed, and digital rectal examination/transrectal ultrasound was performed prior to testosterone therapy initiation and then every 6-12 months.

Over a median follow-up of 8 years and 5,000 patient-years, patients receiving testosterone replacement therapy had a statistically significant increase in prostate volume (2.4 mL, p<0.001) with no appreciable change in the PSA. Men on therapy dropped 18% of their body weight while the control group increased 1.8%. Similarly, CRP levels decreased in the testosterone therapy group and remained unchanged in the control arm. In the testosterone therapy group, 9 men (2.3%) were diagnosed with prostate cancer, compared to the control arm in which 15 (5.1%) men were diagnosed with prostate cancer. The incidence per 10,000 years was 29 in the testosterone group and 102 in in the control group. Interestingly, radical prostatectomy was performed in all men, and in the testosterone group, all men had Gleason score ≤6 disease. The weaknesses of this study include the retrospective design with inherent selection bias, in addition to no long-term prostate cancer outcomes. Second, there is no metric with regards to how hypogonadal the men in the control arm truly were.

The authors concluded that hypogonadal men treated with testosterone therapy may have decreased incidence of prostate cancer compared to hypogonadal men not treated with testosterone. Given the inherent limitations of this study (a few, as such, mentioned above), this study certainly requires prospective validation. The implications of potentially feeling the need to treat all hypogonadal men with testosterone to perceivably decrease their risk of prostate cancer clearly has ramifications.

Presented By: Ahmad Haider, MD, PhD, Private Urology Practice, Bremerhaven, Germany

Co-Authors: Karim Sultan Haider

Written By: Zachary Klaassen, MD, Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
Twitter: @zklaassen_md

at the 2017 ASCO Annual Meeting - June 2 - 6, 2017 - Chicago, Illinois, USA

Reference:
1. Wallis CJ, Lo K, Lee Y, et al. Survival and cardiovascular events in men treated with testosterone replacement therapy: an intention-to-treat observational cohort study. Lancet Diabetes Endocrinol 2016 Jun;4(6):498-506.
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