Family history of breast cancer and inherited genes

Is breast cancer hereditary?

Hereditary means a condition is passed down from parents to their children. Parents cannot pass cancer down to their child. But they can pass down gene changes (mutations). These are called inherited gene changes. Some inherited gene changes can increase your risk of cancer. But most breast cancers are not caused by an inherited gene change. Breast cancer is common. Many people have relatives who have had breast cancer and they will not have inherited a gene change. But there is a pattern of cancers in some families which suggests there might be a gene change in their family.

Family history and breast cancer risk

Having a mother, sister or daughter diagnosed with breast cancer increases your risk of breast cancer. This risk is higher:

• when more close relatives have breast cancer

• if a relative developed breast cancer under the age of 50

But most women who have a close relative with breast cancer will never develop it.

What to do if you are worried about your family history

Speak to your GP. They might refer you for a family history risk assessment. This happens at a specialist breast clinic or a genetic clinic. The specialists at the clinic can tell you more about your risk of developing breast cancer.

Referral to a specialist clinic

UK guidelines help GPs to identify people who might have an increased risk of cancer due to their family history.

Your GP will ask you about your family history. Before your appointment, try to find out as much as you can about your family history.

Your GP will refer you to a specialist breast clinic for any of the following:

• One first degree female relative has had breast cancer before the age of 40.

• One first degree male relative has had breast cancer at any age.

• One first degree relative has had cancer in both breasts. And the first cancer was before the age of 50.

• Two first degree relatives, or one first degree and one second degree relative, have had breast cancer at any age.

• One first degree or second degree relative has had breast cancer at any age. And one first degree or second degree relative has had ovarian cancer at any age. One of these relatives should be a first degree relative.

• Three first or second degree relatives have had breast cancer at any age.

Your GP should also refer you if you have one first degree or second degree relative who has had breast cancer after the age of 40, and one of the following:

• The cancer was in both breasts.

• The cancer was in a man.

• Ovarian cancer.

• Jewish ancestry.

• Sarcoma in a relative younger than age 45 years.

• A type of brain tumour called glioma or childhood adrenal cortical carcinoma.

• A number of cancers have been diagnosed in your family at a young age.

• Two or more relatives with breast cancer on your father's side of the family.

Read NICE guidance about increased risk due to family history

Assessing your family history at the clinic

The specialist at the clinic will ask about the following:

• Your family history on both sides of the family. This includes relatives who haven’t had cancer, and their age when they died.

• The types of cancer in your family, how people are related to each other, and their age at diagnosis.

• Whether any family member have had more than one cancer, or cancer in both breasts.

• Your ethnic background. This is because some ethnicities, such as a Jewish background, mean you are more likely to have a gene change that increases breast cancer risk.

The specialist will understand that you might not be able to answer all of their questions about your family history.

Your breast cancer risk

Your specialist team estimates your breast cancer risk. They consider your family history as well as other risk factors. They will tell you about your risk. They might talk about:

• General population risk - this means your risk of breast cancer is the same or very similar to the general population’s risk.

• Moderate risk – this means your risk of breast cancer is higher than the general population’s risk. But it is still more likely you will not get breast cancer.

• High risk – this means you are more likely to get breast cancer than those with a moderate risk. But it does not mean you will definitely get breast cancer.

What happens next?

This depends on your risk. You can read more about these options further down this page.

General population risk

You will have routine screening. In the UK, the NHS screening programme invites all women from the age of 50 to 70 for screening every 3 years.

Read more about breast cancer screening

It is still important you are aware of what your breasts or chest are normally like. See your GP if you notice any changes that aren’t normal for you.

Read more about finding breast cancer early

Moderate or high risk

Your doctor might offer you regular screening from an earlier age.

They might also discuss medicines to reduce your risk of breast cancer. For example, tamoxifen.

High risk

Your doctor might discuss risk reducing surgery.

They might offer you genetic counselling to talk about possible genetic testing.

Genetic testing for gene changes

You might have genetic testing to find out if you have inherited a gene change that increases your risk of breast cancer. Your specialist team will tell you if it is an option for you.

To begin with, it is often more appropriate to test a family member who is most likely to have the gene change. This is usually someone affected by a relevant type of cancer. It is less common to start off by testing family members who have not had cancer.

It can be difficult to decide what to do. Your doctor or genetic counsellor will help you understand your risk of breast cancer and other cancer types. They can also tell you more about your options for managing your risk of breast cancer.

Gene changes

We know about several gene changes that can increase breast cancer risk. There are tests for some of them. Your team might use different words to describe a gene change. These include fault, variant or mutation.

Changes to the BRCA1 and BRCA2 gene increase your risk of breast cancer. BRCA stands for BReast CAncer gene. Everyone has BRCA1 and BRCA2 genes. They stop cells in our body from growing and dividing out of control. A change in the BRCA1 or BRCA2 gene means that the cells can grow out of control. This can lead to cancer developing.

There are other gene changes that could increase your risk of developing breast and other types of cancer. These include:

• TP53 gene

• PALB2 gene

• ATM gene

• CHEK2 gene

• STK11 gene

• PTEN gene

• RAD51C and RAD51D gene

• CDH1

Find out more about breast cancer genes

Having one of these faulty genes means that you are more likely to get breast cancer than someone who doesn’t. But it is not a certainty.

Remember that most breast cancers happen by chance. Researchers estimate that only around 5 to 10 out of 100 breast cancers (5 to 10%) are caused by an inherited faulty gene.

Read about testing for inherited cancer genes

Ways to manage your risk of breast cancer

There are different options if you have an increased risk of breast cancer.

You can’t change your family history. But there are some other things that can help to reduce the risk of breast cancer. These include keeping a healthy weight and being physically active.

Read more about reducing your risk of breast cancer

Your specialist clinic will discuss the options below with you.

Breast screening for women at increased risk

Breast cancer screening aims to find breast cancer early, when there is the best chance of successful treatment. There are UK recommendations about screening women who have an increased risk of breast cancer. These depend on:

• your age

• your level of risk

• if you have a gene change, and which gene it is

Your specialist clinic will tell you about your own screening options. They will discuss the advantages and disadvantages of screening with you. Below is a simplified version of the recommendations:

• If you have a moderate or high risk of breast cancer because of your family history, you might have yearly mammograms, starting in your forties.

• If you are younger than 40 and have a high risk of breast cancer, you might have screening with either MRI scans or mammograms. This depends on your level of risk and other factors.

The recommendations are slightly different if you have a gene change that increases the risk of breast cancer. UK guidelines recommend yearly MRI scans from:

• age 20 for women with a TP53 gene change

• age 25 for women with a BRCA1 or BRCA2 gene change

Read about breast screening

Medicines for women at moderate or higher risk of breast cancer

Doctors may offer you medicines to lower your risk if you have a moderate or high risk of breast cancer. These medicines are:

• tamoxifen for 5 years if you are pre menopausal

• anastrozole for 5 years if you are post menopausal

• raloxifene or tamoxifen for 5 years if you are post menopausal and you can’t take anastrozole

The National Institute for Health and Care Excellence (NICE) have decision aids on their website. These are to help you decide whether to take tamoxifen. There are different aids depending on your risk, and whether you have been through the menopause. Visit the NICE website to look at the decision aids

At the moment, the evidence from clinical trials is unclear about how helpful these medicines are if you have certain gene changes. This is something you can talk about with your genetics team.

All these medicines have side effects and are not suitable for everyone. Your doctor can tell you:

• whether these are suitable for you

• possible benefits and side effects

• how much they may lower your risk of developing breast cancer

You do not need to take these medicines if you have had surgery to reduce your risk of breast cancer.

Find out more about these medicines and their side effects

Surgery for women at high risk of breast cancer

Doctors call this risk reducing surgery. It involves removing both breasts. It is called a bilateral risk reducing mastectomy:

• bilateral means both sides

• mastectomy means removal of the breast

The surgeon removes as much breast tissue as possible. But it’s not possible to remove it all. So, although surgery lowers your risk it does not go away completely.

You may be able to have a breast reconstruction during the surgery, or at a later date. This is surgery to make new breasts using tissue from elsewhere in your body or implants. Find out more about breast reconstruction

You meet a surgeon, nurse specialist and counsellor before you decide about having surgery. They can talk about:

• your own personal risk of getting breast cancer

• alternative options such as screening or medicines

• what the surgery involves

• your feelings and any concerns you may have

Coping with an increased risk of breast cancer

This can be a difficult time for you and your family. Making a choice about genetic testing, or different treatments is a personal decision. It is important you have all the information you need and you can do what feels right for you. If your test shows that you have an inherited gene change, some members of your family may also be at risk of having that gene change. They may have different views to you about whether to have tests. It is helpful to think this through. Make sure you ask any questions you have. Your doctors and nurses will support you when making your decisions and throughout any treatment you choose. It can help to talk to family and friends about how you feel. Read more about making decisions around genetic testing

You can also contact one of the breast cancer organisations. They have free factsheets and booklets they can send to you. Or you may be able to talk to someone who has been in a similar situation. Find breast cancer organisations and other resources