Comparing two hormone therapy drugs in men with advanced, non-metastatic prostate cancer

This study aimed to compare two hormone therapies, gonadotropin-releasing hormone (GnRH) agonists and anti-androgen therapy (AA) in men with advanced, non-metastatic prostate cancer. This study found that the two therapies have similar outcomes, but by starting with AA treatment may reduce side effects associated with GnRH medication. 

Anti-androgen therapy (AA) is a hormone treatment used for men with prostate cancer. AA drugs such as bicalutamide (Casodex) or flutamide (Eulexin) lower the level of male hormones, like testosterone, active in cancer growth. Another treatment is gonadotropin-releasing hormone (GnRH) agonists such as nafarelin (Synarel) or goserelin (Zoladex). These work by blocking the messages from the brain to the testicles, telling them to make testosterone, thus stopping the production of this hormone. These medications can be used to treat localized prostate cancer. 

Although the goal for these therapies is the same, GnRH drugs are known to be more powerful in reducing testosterone levels. GnRH drugs also have a more severe profile of side effects such as sexual dysfunction, bone loss and an increased risk of fractures or heart disease. It is still unclear which type of hormone treatment is more effective for the treatment of high-risk prostate cancer. 

This study included 6956 patients with high-risk localized (no spread) prostate cancer. 2078 patients had AA treatment and 4878 patients had GnRH medications as primary (first-line) treatment. They were followed up for an average of 4.7 years. 

At 5 years, there were fewer deaths due to prostate cancer for men treated with AA compared to GnRH drugs (16% vs 22%). However, the risk of death from prostate cancer for men on AA and GnRH medication was similar. There was a 23% higher risk of death from all causes in men who took GnRH medication. Men who started on AA often moved onto GnRH medications over time. 

This study concluded that AA and GnRH drugs have a similar effectiveness in patients with high-risk prostate cancer. The authors suggested that GnRH medication and its side effects can be delayed by starting on AA treatment. 

Men managed with AA were younger, diagnosed more recently, had fewer additional medical conditions and had a lower-risk cancer compared to men treated with GnRH agonists.