Hormones are substances produced naturally in the body. They act as chemical messengers and help control the activity of cells and organs. Hormonal therapies interfere with the way hormones are made or how they work in the body.
Most prostate cancers need the hormone testosterone to grow. Almost all testosterone in men is made by the testicles. A very small amount is made by the adrenal glands, which sit above the kidneys.
Diethylstilbestrol reduces the amount of testosterone made by your body. This reduces testosterone levels and may shrink the prostate cancer or stop it growing.