Inherited breast and ovarian cancer
On this page
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About inherited breast and ovarian cancer
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Inherited breast and ovarian cancer genes
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Managing a higher risk of breast and ovarian cancer
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Breast screening
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Ovarian cancer screening
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Risk-reducing breast surgery
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Risk-reducing bilateral salpingo-oophorectomy
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Chemoprevention for breast cancer
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About our information
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How we can help
About inherited breast and ovarian cancer
A small number of people have a breast or ovarian cancer that is linked to gene changes called variants. These gene changes can be passed from parent to child (inherited).
A gene variant that increases the risk of breast and ovarian cancer can cause a pattern of cancer in a family. This is called hereditary breast and ovarian cancer syndrome (HBOC). For example, in the family there may be:
- several people affected by breast cancer or ovarian cancer
- people diagnosed with breast cancer before the age of 50
- people diagnosed with triple negative breast cancer or high-grade serous ovarian cancer
- a man, or person assigned male at birth, diagnosed with breast cancer
- someone who has had breast cancer in both breasts (bilateral breast cancer) or who has had breast and ovarian cancer.
Families from some ethnic groups are more likely to carry a gene variant that increases the risk of breast and ovarian cancer. For example, this includes families from a Central or Eastern European or Ashkenazi Jewish (Central or Eastern European Jewish) background.
Related pages
Worried about hereditary breast and ovarian cancer syndrome?
Many people have someone in their family who is affected by breast or ovarian cancer. Most of these cases are not likely to be caused by an inherited gene variant.
If you are worried about the pattern of cancer in your family, or a test has shown that someone in your family has a cancer gene variant, talk to your GP. If needed, they will refer you to a genetics specialist. The specialist can give you more advice and information. They will explain whether genetic counselling or genetic testing is likely to be useful.
Inherited breast and ovarian cancer genes
Some gene variants can increase the risk of breast and ovarian cancer. If genetic testing shows you have 1 of these variants, this does not mean you will definitely get cancer. But you may have an increased risk of some types of cancer.
Your genetics specialist will explain more about your risk. They will also give you information about ways to manage your risk. The information they give you will depend on:
- your sex assigned at birth (male or female)
- your age
- the type of gene variant
- your family history of cancer
- your medical history
- other factors in your lifestyle – for example, diet or smoking.
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BRCA1 and BRCA2
The genes most often linked to breast and ovarian cancer are called BRCA1 and BRCA2.
Women, and people assigned female at birth, with a BRCA1 or BRCA2 gene variant have a high risk of developing breast or ovarian cancer during their lifetime. They may also have a slightly higher-than-average risk of some other cancer types.
Men, and people assigned male at birth, with a BRCA1 or BRCA2 variant may have a higher-than-average risk of prostate cancer, breast cancer and some other cancer types.
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PALB2
Women, and people assigned female at birth, with a PALB2 gene variant have a high risk of developing breast cancer during their lifetime. They may also have a slightly higher-than-average risk of some other cancer types, including ovarian and pancreatic cancer.
Men, and people assigned male at birth, with a PALB2 variant may have a slightly higher-than-average risk of breast cancer and pancreatic cancer.
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ATM
Women, and people assigned female at birth, with an ATM gene variant have a moderately higher-than-average risk of breast cancer during their lifetime. A small number of people have an ATM gene variant called c.7271T>G. They have a higher risk of developing breast cancer during their lifetime.
Men, and people assigned male at birth, with an ATM gene variant may have a slightly higher-than-average risk of some other cancer types. But more research is needed to understand this.
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CHEK2
Women, and people assigned female at birth, with a CHEK2 gene variant have a moderately higher-than-average risk of developing breast cancer during their lifetime. They may also have a slightly higher-than-average risk of some other cancer types. But more research is needed to understand this.
Men, and people assigned male at birth, with a CHEK2 gene variant may have a slightly higher-than-average risk of some other cancer types. But more research is needed to understand this.
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RAD51C and RAD51D
Women, and people assigned female at birth, with a RAD51C or RAD51D gene variant have a higher risk of developing ovarian cancer during their lifetime. They may also have a higher-than-average risk of breast cancer.
Men, and people assigned male at birth, can carry a RAD51C or RAD51D gene variant. More research is needed to understand possible cancer risks. But it is not thought to be high.
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BRIP1
Women, and people assigned female at birth, with a BRIP1 gene variant have a higher risk of developing ovarian cancer in their lifetime.
Men, and people assigned male at birth, can carry a BRIP1 gene variant. More research is needed to understand possible cancer risks. But it is not thought to be high.
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TP53 (Li-Fraumeni syndrome)
Li-Fraumeni syndrome is a rare condition caused by a TP53 gene variant. People affected by this condition have a high risk of several different cancer types, including breast cancer. The George Pantziarka TP53 Trust offers support and information for families affected by Li-Fraumeni syndrome.
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CDH1 (hereditary diffuse gastric cancer)
A CDH1 gene variant causes a high risk of stomach cancer during a person’s lifetime. This condition is called hereditary diffuse gastric cancer.
Women, and people assigned female at birth, with a CDH1 gene variant also have a high risk of developing a type of breast cancer called lobular breast cancer. The Genetic Alliance offers information and support about rare inherited conditions.
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STK11 (Peutz-Jeghers syndrome)
Peutz-Jeghers syndrome is a rare condition caused by an STK11 gene variant. People affected by this condition have a high risk of several different cancer types, including breast cancer, ovarian cancer and bowel cancer. The Polyposis Registry has more information about Peutz-Jeghers syndrome.
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NF1 (neurofibromatosis type 1)
Neurofibromatosis type 1 is a rare condition caused by an NF1 gene variant. People affected by this condition have a moderate risk of several different cancer types, including breast cancer. The Genetic Alliance offers information and support about rare inherited conditions.
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PTEN (Cowden syndrome)
Cowden syndrome, or PTEN hamartoma tumour syndrome, is a rare condition caused by a PTEN gene variant. People affected by this condition have a high risk of several different cancer types, including breast cancer and bowel cancer. PTEN UK & Ireland offers information and support to people affected by PTEN gene variants.
There are likely to be gene variants that experts currently do not know about. This means some families may have a clear pattern of breast or ovarian cancer, but genetic tests do not find a variant.
Managing a higher risk of breast and ovarian cancer
If your family history or a genetic test shows you have a higher risk of breast or ovarian cancer, there may be ways to reduce or manage that risk. Your genetics specialist will explain whether any of the following might help in your situation.
Cancer screening tests
Risk-reducing treatments
Women, and people assigned female at birth, with a high risk of breast and ovarian cancer may be offered:
- surgery to remove the breasts – this is called risk-reducing breast surgery or mastectomy
- surgery to remove the ovaries and fallopian tubes – this is called risk-reducing bilateral salpingo-oophorectomy
- a risk-reducing drug for a number of years – this is called chemoprevention.
Being aware of the symptoms of breast and ovarian cancer
Lifestyle changes
Breast screening
Breast screening is a way of finding signs of early breast cancers that are too small to see or feel. It does not prevent breast cancer, but it can help find it at an early stage, when many breast cancers can be cured.
The NHS offers screening from the age of 50, every 3 years. During screening, doctors or nurses use low-dose x-rays called mammograms to take pictures of each breast.
If you have a high risk of breast cancer, you may be offered breast screening at a younger age and more often. You may also be offered screening with an MRI scan of the breast.
Your genetics specialist will talk to you about your level of risk. Depending on this and your age, they will explain:
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The types of screening you may have
You may have a mammogram, an MRI scan or both. This will depend on your age, the type of gene variant and how dense your breast tissue is. Dense breast tissue is mostly made of glandular and connective tissue. It has very little fatty tissue. This makes it harder to see a cancer using mammograms.
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The age you should start being offered screening
This may depend on the pattern of cancer in your family and the type of gene variant.
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How often you should have screening
Your genetics specialist should also explain what age this might change.
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The possible benefits and disadvantages of screening
The aim of screening is to save lives from breast cancer. But it is important that you also understand the possible disadvantages before you decide whether to have screening. For example, screening may find something that needs further tests but that is found to be harmless. This can cause a lot of worry.
Ovarian cancer screening
In the UK, screening is not usually offered for ovarian cancer. Current screening tests cannot find ovarian cancer early enough to make it more treatable. Researchers are still trying to find the most effective way to screen for ovarian cancer. Ovarian cancer screening is sometimes available as part of a clinical trial.
Risk-reducing breast surgery
Some gene variants and patterns of cancer in a family may cause a very high risk of breast cancer. In this case, you may be offered risk-reducing breast surgery. This means surgery to remove both breasts. It is also called a risk-reducing mastectomy. Breast reconstruction to make new breast shapes can be done at the same time.
Surgery does not remove the risk of breast cancer completely. But it may reduce your risk of developing breast cancer by about 95%. This means that if 100 people with a very high risk of breast cancer have surgery, 95 will not develop breast cancer in their lifetime. 5 of the 100 people (5%) will develop breast cancer despite having surgery.
Making a decision about having this type of surgery can be complicated. We have more information about what risk-reducing breast surgery involves and things to think about before you make a decision.
Risk-reducing bilateral salpingo-oophorectomy
Surgery to remove the ovaries and the fallopian tubes is called a bilateral salpingo-oophorectomy.
At the moment, there is no way to screen for signs of early ovarian cancer. Surgery may reduce your risk of cancer in or near the ovary by over 95%. This means more than 95 out of 100 people who have this surgery will not develop ovarian cancer in their lifetime. Less than 5 of the 100 people (5%) will develop cancer despite having the surgery.
You may be offered this surgery if you have a high risk of ovarian cancer due to:
- a gene variant that increases your risk
- the pattern of cancer in your family.
Your genetics specialist will explain more about your situation. They will talk to you about your overall lifetime risk of developing ovarian cancer and your risk at different ages. If surgery is an option, they will give you information about the possible risks and benefits of having surgery. They will discuss the age at which you should consider having the operation.
Removing the ovaries will cause an early menopause if you have not already had it. It will also mean you will no longer be able to get pregnant. Some people choose to delay the operation until they are sure they no longer want to get pregnant.
After surgery, you usually take hormone replacement therapy (HRT) until the age you would be expected to have the menopause. This is usually around the age of 50. HRT protects your bones and heart health and helps prevent menopausal symptoms. In this situation, HRT does not increase the risk of breast cancer.
Chemoprevention for breast cancer
Chemoprevention means using drugs to reduce the risk of certain types of cancer. If you have a higher risk of breast cancer, you may be offered anti-oestrogen drugs to reduce this risk. Treatment involves taking a tablet every day for 5 years.
How much this treatment reduces your risk of developing breast cancer depends on:
- the type of gene variant you have
- your family history.
Some people will develop breast cancer despite taking this treatment.
Your genetics specialist will explain more about your situation. They will give you information about the possible risks and benefits of having treatment and the possible side effects of the drug.
The drugs most commonly used are tamoxifen, anastrozole or raloxifene. If you have not been through the menopause, you will usually be offered tamoxifen. You need to use contraception while taking it. It is not suitable if you are trying to get pregnant.
If you have been through the menopause, you may be offered anastrozole, tamoxifen or raloxifene.
Side effects
The most common side effects of these drugs are menopausal symptoms. This can include:
- hot flushes
- vaginal discharge and dryness.
Your doctor or nurse will give you more information about possible side effects.
Tamoxifen can also slightly increase your risk of womb cancer and blood clots. These problems are more common in people who take tamoxifen after they have had the menopause.
Anastrozole can increase the risk of bone thinning. This is called osteoporosis. Tamoxifen can also increase this risk when taken before the menopause. If you are at risk of osteoporosis, you may be given drugs to help protect your bones.
About our information
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References
Below is a sample of the sources used in our family history and cancer information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk
Monahan KJ, Bradshaw N, Dolwani S, et al. Guidelines for the management of hereditary colorectal cancer from the British Society of Gastroenterology (BSG)/Association of Coloproctology of Great Britain and Ireland (ACPGBI)/United Kingdom Cancer Genetics Group (UKCGG). Gut. 2020; 69: 411–444. Available from DOI: 10.1136/gutjnl-2019-319915 (accessed October 2022).
NICE. Familial breast cancer: classification, care and managing breast cancer and related risks in people with a family history of breast cancer. Clinical guideline [CG164]. Last updated: 20 November 2019. Available from https://www.nice.org.uk/guidance/CG164 (accessed October 2022).
NICE. Molecular testing strategies for Lynch syndrome in people with colorectal cancer. Diagnostics guidance [DG27]. Published: 22 February 2017. Available from https://www.nice.org.uk/guidance/dg27 (accessed October 2022).
NICE. Testing strategies for Lynch syndrome in people with endometrial cancer. Diagnostics guidance [DG42]. Published: 28 October 2020. Available from https://www.nice.org.uk/guidance/dg42 (accessed October 2022).
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Reviewers
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. It has been approved by Senior Medical Editor, Dr Marc Tischkowitz, Reader and Honorary Consultant Physician in Medical Genetics.
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