Hormone Therapy

Hormones are chemical messages produced by some parts of the body that cause changes in other parts. For example, the ovaries produce the female sex hormone oestrogen, while the pancreas produces insulin, which affects how we absorb glucose from the blood.
We now know that hormone systems are implicated in some types of cancer; for example, oestrogen encourages some types of breast cancer to grow faster. By tinkering with the body's hormone system in the right way, doctors can stop some cancers growing and even kill them

read more http://info.cancerresearchuk.org/cancerandresearch/learnaboutcancer/treatment/hormonetherapy/?a=5441