Androgen deprivation therapy aims to lower concentrations of the male hormone testosterone in the body that can stimulate prostate cancer cells to grow. This type of hormone therapy is an established treatment for prostate cancer that has spread to other parts of the body. However, its role in treating localised prostate cancer is less clear.
Professor Jim Denham (Trans-Tasman Radiation Oncology Group, University of Newcastle, New South Wales, Australia) and colleagues recruited over 800 men with locally advanced prostate cancer from 19 centres in Australia and New Zealand. Patients were randomly assigned radiotherapy and either no testosterone suppression, 3 months' suppression or 6 months' suppression. When compared with men treated by radiotherapy alone, men treated with three months of goserelin and flutamide prior to and during radiotherapy had a 35% lower chance of relapse. For men treated with six months of hormone therapy prior to and during radiotherapy the risk of relapse was reduced by 44%.
Professor Denham states: "We have demonstrated a role for short-term testosterone suppression in the treatment of locally advanced prostate cancer...Our data suggest that 3 months' testosterone suppression reduced the risk of cancer returning in the prostate itself, but did not reduce the risk of spread of cancer to other parts of the body or increase cancer survival. However, 6 months testosterone suppression reduced the chances of cancer returning in the prostate even more. More importantly, it also reduced the chances of cancer spreading. Men treated this way, therefore, lived longer." (Quote by e-mail; does not appear in published paper)