Hormones are substances produced naturally in the body. They act as chemical messengers and help control the activity of cells and organs. Hormonal therapies are drugs that 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 above the kidneys.
Goserelin stops the testicles from making testosterone. This reduces testosterone levels and may shrink the prostate cancer or stop it growing.
Some breast cancers need a hormone called oestrogen to grow. Goserelin may be given with other types of hormonal therapies to reduce oestrogen levels. This may shrink a breast cancer or stop it growing.