Our bodies are made up of billions of tiny cells. Normally, cells grow and multiply in an orderly way. New cells are only made when and where they're needed.
In cancer, this orderly process goes wrong and cells begin to grow and multiply out of control.
In ovarian cancer, cells in the ovary start to change and grow abnormally. If the cancer is not identified at an early stage, it can spread to nearby parts of the body, including other parts of the female reproductive system.
We don't know the causes of ovarian cancer, but there are risk factors that may make developing the condition more likely. Some of these risk factors cannot be changed, but there may be some that can. Although these factors may increase the risk of ovarian cancer, you can still get it even if none of them apply to you.
Possible causes and risk factors of ovarian cancer
Generally, it's not possible to say what causes ovarian cancer in an individual woman. However, some features are more common among women who have developed ovarian cancer. These features are called risk factors. Having certain risk factors increases a woman's chance of developing ovarian cancer.
Having one or more risk factors for ovarian cancer doesn't mean a woman will definitely develop ovarian cancer. In fact, many women with ovarian cancer have no obvious risk factors.
Known risk factors for ovarian cancer include:
- getting older: women who are over 50 are more likely to develop ovarian cancer than younger women
- inheriting a faulty gene (called a gene mutation) that increases the risk of ovarian cancer
- having a strong family history of ovarian cancer, breast cancer, or some other cancers, including colorectal cancer and endometrial cancer
Only around 5-10% of all ovarian cancers are due to inherited factors.
Research suggests that the risk of ovarian cancer is slightly higher for women who:
- have medical conditions such as endometriosis
- use long-term hormone replacement therapy (HRT)
- had early puberty (menstruating before 12) or late menopause (onset after 50)
- smoke cigarettes
- are obese
Women have a lower risk of developing ovarian cancer if:
- they had a baby before the age of 26
- they used oral contraceptives (the pill) for at least 3 months
- they have had a hysterectomy (removal of the uterus) and tubal ligation (tubes tied)
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Last reviewed: December 2017