Most men with prostate cancer have an excellent prognosis, but for men with high-risk prostate cancer, adding another medication at the start of treatment, not waiting until the first treatment fails, can increase survival.
Background: The standard medical treatment for most advanced prostate cancer is androgen-deprivation therapy—injected drugs such as leuprolide (Lupron), which halt the body’s production of the hormone that fuels the growth of the cancer. But in some cases, prostate cancer cells are able to convert hormonal precursors directly into testosterone, bypassing the medication’s ability to control the cancer. Previous studies have found that giving men abiraterone acetate has improved survival in men with cancer that was resistant to typical androgen-deprivation therapy.
Abiraterone works by blocking the action of an enzyme required to produce androgens and by partially blocking the testosterone receptor in the cancer cells. Recently, researchers investigated whether treatment with abiraterone should begin at the same time as androgen-deprivation therapy—rather than waiting for it to fail—for men whose cancer has spread, either locally or throughout the body.
Study: More than 1,900 men from the UK and Switzerland who were newly diagnosed with metastatic or high-risk prostate cancer were enrolled in the study. All of the men received androgen-deprivation therapy…and half of them received combination therapy, which also included abiraterone and prednisolone, a steroid. (Prednisolone is needed to compensate for the loss of other hormones related to use of abiraterone.) The duration of treatment depended on the participants’ cancer but was capped at two years or until any type of progression. For some men in either group, radiation therapy was also added, depending on the features of their cancer.
Results: By the end of study, 262 men in the androgen-therapy alone group had died, compared with 184 in the combination therapy group. At three years, more men in the combination group were alive without any signs of treatment failure (75% versus 45%). The improved survival came with higher risk of adverse “events,” however (47% versus 33%). The most common adverse effects in both groups were hot flashes and impotence, but high blood pressure and abnormal liver function were more common in men receiving combination therapy, most likely because of the long-term use of steroid.
Bottom line: For men facing metastatic or high-risk prostate cancer, starting treatment off with abiraterone along with standard androgen-deprivation therapy increases survival by 37%. As with any medication, of course, the benefits of abiraterone combination therapy must be balanced against the potential risks of the therapy.