Treatments available for metastatic hormone-resistant prostate cancer

The authors identified treatments available for men with advanced prostate cancer who were resistant to hormone therapy (castration-resistant). 

Hormone therapy is a standard treatment for prostate cancer. It targets the male sex hormones active in prostate cancer, such as testosterone. Some patients can develop a resistance to hormone therapy and will require different treatments.

In advanced stages of this disease, the cancer spreads from prostate to other parts of the body (metastasis). Systemic therapies can be used to treat metastatic hormone-resistant prostate cancer. Systemic therapy is a treatment that reaches cancer cells through out the body.. It can include hormone therapy, chemotherapy and immunotherapy. Immunotherapy uses body’s own immune cells to fight cancer.

The authors aimed to identify treatments available for metastatic hormone-resistant prostate cancer.

Abiraterone acetate:

Patients treated with abiraterone acetate (Zytiga) and prednisone (Deltasone) experienced a 57% improvement in progression-free survival (time following treatment before the disease progressed ) compared to the control group.. The control group received placebo plus prednisone.  Patients treated with abiraterone acetate also experienced a delay in pain of 26.7 months compared to 18.4 months in the control group. Patients treated with abiraterone acetate also experienced a delay in functional decline (ability to function on a normal level) of 12.7 months. This was compared to 8.3 months in the control group.

Results were supported by other studies, which concluded that abiraterone acetate increased progression-free survival, overall survival (patients who were still alive after treatment) and time until prostate specific antigen progression (PSA – protein elevated in the blood when prostate cancer was present).

Docetaxel:

Patients who received docetaxel (Taxotere) plus prednisone every 3 weeks reported a significant increase in overall survival of 19.2 months. This was compared to 16.3 months in patients who received mitoxantrone (Novantrone) plus prednisone. However, docetaxel patients experienced more severe side effects. Patients who received docetaxel, prednisone and bevacizumab (Avastin) experienced an improved progression-free survival of 9.9 months compared to 7.5 months in the control group. The control group received docetaxel plus prednisone. However, there was a significant increase in treatment-related side effects, including death, compared to the control group.

Enzalutamide:

Patients treated with enzalutamide (Xtandi) had an overall survival of 18.4 months compared to 13.6 months in the control group. Progression-free survival was 8.3 months in patients treated with enzalutamide compared to 2.9 months in the control group. Quality of life benefits (patients’ ability to function on a social, mental and physical scale) were observed in 43% of patients compared to 18% in the control group.

The authors concluded that treatments such as docetaxel, abiraterone acetate and enzalutamide were successful in the treatment of metastatic hormone-resistant prostate cancer.