A Phase III study showed that patients with high-risk prostate cancer who received 18 months of hormone therapy lived as long as patients treated for 36 months.

The finding suggests that the currently recommended duration of hormone therapy – also known as androgen blockade therapy – of 24-36 months can be safely shortened without affecting survival.

“Shorter-term hormone therapy could have a big impact on the lives of men with prostate cancer, reducing the quantity and intensity of its unpleasant side effects as well as treatment costs,” said lead author Abdenour Nabid, MD, Fellow of the Royal College of Physicians of Canada and associate professor at Centre Hospitalier Universitaire de Sherbrooke in Sherbrooke, Canada. 

“For the benefit of the patients, we hope these results will convince doctors that they can stop hormone therapy after one and a half year instead of two to three years.”

In the study, 630 patients with high-risk, node-negative (localized) prostate cancer were randomly assigned to receive either 36 or 18 months of androgen blockade therapy (bicalutamide and goserelin) before, during, and after pelvic and prostate radiotherapy.

At a median follow-up of 77 months, comparable numbers of patients were still alive in the two treatment groups – 77.1 percent in the 36-month group and 76.2 percent in the 18-month group. Five-year and 10-year overall survival rates were also comparable in the 36-month and 18-month groups – 92.1 percent vs. 86.8 percent and 63.6 percent vs. 63.2 percent for the two groups, respectively.

Assessment of cancer-specific survival showed that halving the duration of androgen blockade therapy didn’t affect the odds of dying of prostate cancer (10-year disease-specific survival was 87.2 percent in both groups).

Long-term androgen blockade therapy is a standard treatment for men diagnosed with localized prostate cancer. The goal of this therapy is to block the body’s ability to produce the hormone testosterone, which fuels the growth of prostate cancer. Prolonged suppression of testosterone production, however, causes a wide range of physical, mental, and emotional side effects in men, including hot flashes, loss of libido, erectile dysfunction, weight gain, loss of bone density, loss of muscle mass, and depression. 

Many of those side effects worsen over the duration androgen blockade therapy. It is therefore expected that shorter-course treatment will result in improved quality of life. A quality of life analysis for this study, still in progress, marks the longest quality of life follow-up among patients with prostate cancer to date.

Source: ASCO