Causes and risk factors of ovarian cancer
Doctors do not know what causes cancer to start in the ovary, fallopian tube or peritoneum. But some risk factors may increase the chances of it developing.
Causes and risk factors of cancer of the ovary, fallopian tube or peritoneum
Doctors do not know what causes cancer to start in the ovary, fallopian tube or peritoneum. But some risk factors may increase the chances of it developing.
Doctors know less about the risk factors for cancers that start in the fallopian tube or peritoneum (primary peritoneal cancer). This is because these cancers are less common. But doctors think the risk factors are generally the same as the risk factors for epithelial ovarian cancer.
Having a risk factor does not mean you will get cancer. And if you do not have any risk factors, this does not mean you will not get cancer.
If you are worried about ovarian cancer and would like to talk to someone, we are here. You can:
- Call the Macmillan Support Line for free on 0808 808 00 00.
- Chat to our specialists online.
Age
The risk of ovarian cancer increases as you get older. More than a quarter of women diagnosed (25%) are aged 75 and over. After 79 years old, the number of women diagnosed becomes less again.
Hormonal factors
Doctors think the risk of ovarian cancer may be linked to how many times an ovary releases an egg (ovulation). This is because there is evidence that being pregnant, breastfeeding or taking the combined oral contraceptive pill can reduce the risk of ovarian cancer.
Hormone replacement therapy (HRT)
Taking HRT slightly increases the risk of ovarian cancer. The risk is higher if you take oestrogen-only HRT after the menopause. About 4 in 100 ovarian cancers (4%) may be linked to taking HRT. But doctors think this is only for serous and endometrioid ovarian cancers.
Breast cancer
If you have had breast cancer, you may be more likely to develop ovarian cancer. This may be because they have similar risk factors. But doctors think it may be because both cancers can be caused by the same cancer genes.
Asbestos
Asbestos is a material that was previously used in the building industry. It has been banned in the UK for many years.
Prolonged or close contact with asbestos increases the risk of ovarian cancer.
Other conditions
The following conditions can increase your risk of ovarian cancer.
Diabetes
Diabetes is a condition where there is too much glucose in the blood. Glucose is a type of sugar. Having diabetes may increase the risk of ovarian cancer.
Endometriosis
Endometriosis is a non-cancerous condition where the cells that line the womb are found outside the womb. It may slightly increase the risk of endometrioid and clear cell ovarian cancers. These types of ovarian cancer are often diagnosed at an earlier stage.
Lifestyle factors
Some lifestyle factors may increase the risk of ovarian cancer.
Weight
Being overweight or obese may increase the risk of some types of ovarian cancer.
Smoking
Smoking does not affect your risk of the most common type of ovarian cancer. But it may slightly increase the risk of a less common type called mucinous cancer.
Family history of ovarian cancer
Having a family history of ovarian cancer can increase your risk of developing it. If your mother or sister has had ovarian cancer, your risk of certain types may be up to 3 times higher. Your risk may be higher if they were diagnosed at a young age.
Your GP can also give you information and support. If they think your family might have an increased risk of ovarian cancer, they may arrange for you to see a genetics specialist.
We have more information for people who are worried about a family history of ovarian cancer. Your GP can also give you information and support. If they think your family might have a higher risk of cancer, they may arrange for you to see a genetics specialist.
Inherited genetic conditions
About 2 in 10 ovarian cancers (20%) may be caused by a change (variant) in a gene that is passed from parent to child (inherited). Genes contain our genetic information, which is passed on from our parents. Some cancers may affect several people in the same family – for example, breast, bowel, ovarian and womb cancer. Cancers caused by inherited genetic conditions can develop at a younger age.
BRCA1 and BRCA2
The most commonly affected genes are called BRCA1 and BRCA2. If you have a change in either of these genes, you have an increased risk of some cancers. This includes ovarian cancer.
If you have a change in the BRCA1 gene, your risk of ovarian cancer may be up to 65% higher. With BRCA2, it may be up to 30% higher.
All ethnic backgrounds can be affected by an inherited gene change linked to cancer. But the risk of a BRCA gene change is particularly high among people with a Central or Eastern European Ashkenazi Jewish (Central or Eastern European Jewish) background.
Genetic conditions
Lynch syndrome and Peutz-Jeghers syndrome are both inherited genetic conditions. Both can increase the risk of some cancers, including ovarian cancer.
About our information
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.
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References
Below is a sample of the sources used in our ovarian cancer information. If you would like more information about the sources we use, please contact us at informationproductionteam@macmillan.org.uk
Ovarian cancer: recognition and initial management. Clinical guideline [CG122] Published: 27 April 2011 Last updated: 02 October 2023 www.nice.org.uk/guidance/cg122 (accessed May 2024)
Ovarian cancer: identifying and managing familial and genetic risk. NICE guideline [NG241]. Published: 21 March 2024 www.nice.org.uk/guidance/ng241 (accessed May 2024)
A. González-Martín, P. Harter, A. Leary, D. Lorusso, R. E. Miller, B. Pothuri, I. Ray-Coquard, D. S. P. Tan, E. Bellet, A. Oaknin & J. A. Ledermann, on behalf of the ESMO Guidelines Committee. Newly diagnosed and relapsed epithelial ovarian cancer: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up. Published August 17, 2023. www.annalsofoncology.org/article/S0923-7534(23)00797-4/fulltext (accessed May 2024)
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