The causes of ovarian cancer are largely unknown. There are however some factors than can put people at higher risk.

Age

Ovarian cancer is most common in people over the age of 55, but it can occur at a younger age. There are many different types of ovarian cancer, and some are more common in younger people. Younger people tend to be affected by rarer types of ovarian cancer.

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Family history

A family history of breast, ovarian and some other cancers can suggest that a gene variation is being inherited through generations. This gene change increases the risk of developing certain cancers, including ovarian. 

The two best known genes involved in inherited ovarian cancer are BRCA1 and BRCA2. These genes can carry a variation that increases the risk of breast, ovarian, prostate and pancreatic cancer and can be inherited from male as well as female family members.  

Around per cent of cases of ovarian cancer are thought to be linked to these genes.

Find out more about testing for the BRCA gene here.

Information about Lynch syndrome, a genetic condition linked to ovarian cancer, can be found here.

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Watch our webinar on genetic testing with Dr Terri McVeigh, Consultant Clinical Geneticist MB BAO BCh. (Hons), PGCert (Medical Genetics), PGDip (Med. Sci.), MSc (Clin. Ed.), PhD, MRCS. Recorded in May 2022.

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No pregnancies

Ovulation is thought to contribute to the development of ovarian cancer, as the ovary’s DNA is damaged each time ovulation occurs. So in theory the fewer times a person ovulates in their lifetime, the lower their risk of ovarian cancer will be. Ovulation usually stops during pregnancy, so this can reduce the lifetime risk of ovarian cancer. Similarly, using contraceptives that prevent ovulation can reduce the risk of ovarian cancer.

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Personal history of cancer

You have an increased risk of ovarian cancer if you've had breast cancer in the past. The risk is higher in women diagnosed with breast cancer at a younger age, and those with oestrogen receptor negative (ER negative) breast cancer.

Women who had bowel cancer at a young age have an increased risk of ovarian cancer compared to the general population. The increase in risk of ovarian cancer after previous cancer is likely to be partly due to inherited gene variations such as BRCA 1 and 2, and Lynch syndrome.

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Using Hormone Replacement Therapy (HRT)

Using HRT after the menopause increases the risk of ovarian cancer. In the UK, less than 1 in 100 (1 per cent) of ovarian cancers are linked to HRT use. Remember that the increase in risk is small and HRT is helpful for many people with menopausal symptoms so always discuss your individual situation with your GP.

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Smoking

Smoking can increase the risk of certain types of ovarian cancer such as mucinous ovarian cancer. The longer you have smoked, the greater the risk.

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Asbestos

The International Agency for Research on Cancer (IARC) classify asbestos as a cause of ovarian cancer.

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Talcum powder

The International Agency for Research on Cancer (IARC) classify use of talc on genitals as having limited or probable evidence for increasing the risk of ovarian cancer.

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Radiation

There is some evidence to link radiation with an increased risk of ovarian cancer. A very small number of ovarian cancer cases may be caused by radiotherapy for a previous cancer.

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Medical conditions

Studies have shown that people with endometriosis or diabetes have an increased risk of ovarian cancer. In people with diabetes, the increase in risk might be higher in those that use insulin.

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Being overweight or obese

Having excess body fat is linked to an increase in risk of ovarian cancer.