Certain parts of your body make hormones that tell your cells what to do. These hormones are chemical messengers that travel through the blood and control how tissues and organs work. Hormones made naturally by the body are called endogenous hormones. If the levels of certain hormones are too high, they can make our cells grow and divide more quickly than usual. This can increase the risk of cancer.
Some endogenous hormones can increase your chances of developing certain types of cancer. For example, the longer a woman is exposed to estrogen – even when it’s naturally occurring – the greater her risk of breast cancer. So, women who start menstruating at a younger than usual age, go into menopause late or never get pregnant are at a higher-than-average risk of breast cancer, because all of these factors increase her lifetime exposure to estrogen.
For men, long-term exposure of prostate cells to testosterone plays a role in prostate cancer development. The risk of prostate cancer increases as men grow older as their prostate cells are exposed to testosterone for a longer period of time.
Artificial hormones
Sometimes a person can get artificial hormones from outside sources, such as drugs or chemicals in the environment. Hormones from outside sources can raise or lower hormone levels in the body. It’s possible that these changes in hormone levels can increase the risk of cancer.
Endocrine disruptors
Recent studies have focused on a group of chemicals called endocrine disruptors. These chemicals can interfere or disrupt the function of the endocrine system. They can disrupt the endocrine system in a few ways, such as by:
- mimicking the action of certain naturally-occurring hormones, such as estrogen, in the body
- blocking the action of certain hormones
- interfering with the production of hormones or hormone receptors
- altering the chemical messages sent by hormones
The concern is that endocrine disruptors could change the action of hormones in our bodies and lead to health problems, such as cancer. The evidence linking most endocrine disruptors to cancer so far has generally been poor or not consistent.