Triptorelin better than surgical castration in lowering testosterone levels
Compared with subcapsular orchiectomy, 24-week depot triptorelin injections significantly reduce testosterone levels, according to a Danish study.
“To our knowledge this is the first randomized study to demonstrate a difference in treatment effect between surgical and medical castration on testosterone levels,” researchers said.
A total of 58 consecutive hormone naïve men diagnosed with advanced prostate cancer from September 2013 to March 2015 were randomly assigned 1:1 to either subcapsular orchiectomy or triptorelin 22.5 mg given as 24-week depot injections. Follow-up was 48 weeks.
Liquid chromatography-tandem mass spectrometry was used to measure androgen status prior to treatment and after 12, 24, and 48 weeks. Longitudinal Tobit regression was used to analyse between-group differences in achieved hormone levels.
Patients treated with the luteinizing hormone-releasing hormone agonist triptorelin had 29-percent lower testosterone levels (95 percent CI, 17.2 to 41.7) compared to subcapsular orchiectomy (p<0.001). Compared to men undergoing orchiectomy, a significantly higher proportion of men receiving triptorelin had testosterone levels <20 ng/dl at weeks 12 (97 vs 79 percent) and 48 (100 vs 87 percent; p<0.05).
No detectable difference was observed in the adrenal androgen reduction between the two treatment groups.
“Recent evidence suggests that reaching the lowest achievable levels of testosterone with androgen deprivation therapy delays disease progression and increases overall survival in men with advanced prostate cancer,” according to researchers.
In a previous study, participants on luteinizing hormone-releasing hormone agonist therapy showed significantly lower testosterone levels than men who underwent surgical castration. All patients had serum testosterone values <50 ng/dl and 97 percent had testosterone concentrations <20 ng/dl. [J Urol 2012;187:1601-6]