Breast cancer is a serious illness that impacts millions of women worldwide. It is the second most common cancer amongst women, with studies suggesting that every 14 in 100 women are at risk of developing breast cancer during their lifetime.

Factors including age, lifestyle, diet and environment can contribute to the development of cancer. For some people however, the risk of developing breast cancer is higher because they have inherited mutated or what is referred to as “altered” genes. And because genes come from a person’s parents, a person who inherits “altered” genes has had them since birth.

Genetic testing can be used to find out whether a person has inherited altered genes such as:

• BRCA1 and BRCA2

• PALB2

• CHEK2

• ATM

• RAD51C and RAD51D

There are other less common types of altered genes which can increase the chances of breast cancer developing, as well as other cancers.

Do altered genes only affect women?

Men and women can both inherit, carry and pass on altered genes that increase the risk of breast cancer.

It is unlikely that a man who inherits an altered gene will develop breast cancer himself, but the altered gene can be passed on to any children that he has. Therefore, when considering family history of breast cancer, it is important to consider relatives on both sides of the family.

Who is eligible for genetic testing for breast cancer?

A person may be eligible for genetic testing where:

1. There is a significant family history of breast or ovarian cancer

2. An altered gene has already been identified in their family

3. The person has a Jewish background

4. A person has had or has breast or ovarian cancer and meets other criteria

Genetic testing is available through the NHS. A person should discuss genetic testing with a genetics clinician who will be in a position to provide medical advice and further guidance in relation to eligibility for genetic testing.

What does genetic testing involve?

Stage 1: a full screen (diagnostic)

Diagnostic genetic testing involves taking a blood sample which is examined to assess whether an altered gene is present which is linked to breast cancer or other related cancers. If the person has a family history of cancer, further diagnostic testing may be offered as other genetic factors may be involved. The test results are returned within 10 weeks.

Stage 2: a predictive genetic test (targeted genetic test)

This is also known as “cascade” testing. It involves other blood relatives being tested to see whether they also carry the identified altered gene. The test results usually take around 2 to 6 weeks to be returned.

If a person is determined to be at higher risk of getting cancer, they may be offered:

• Regular checks that can find cancer before presenting with any symptoms (the earlier cancer is caught the better it can be treated);

• Treatment that lowers the risk of getting cancer; and

• Support with making lifestyle changes that may lower their risk of getting cancer.

The decision to have genetic testing

A person who is eligible for genetic testing must still make the important decision of choosing whether to have the test or not. A person who is deemed suitable for genetic testing may not want to be tested for a number of reasons. It is not a straightforward decision and those who are faced with this decision will understandably need to balance several difficult and complex factors.

If a person decides to have the genetic testing done and is found to have an altered gene, steps can be taken to manage cancer risk e.g. regular breast screenings or tailored treatment. It can also give other family members an opportunity to consider their own risk being assessed.

By contrast, a person finding out they have inherited an altered gene may cause them feelings of worry and distress. If a person is young, certain treatment options may not be available to them. Further, a positive result may result in family members needing to decide if they would also like to be tested which for some, may not be considered a good thing.

Support to make the decision

The positive news is that the NHS offers genetic counselling for those considering genetic testing. The genetics teams can provide information, support and guidance for people in making their decision. They also offer post-test support in some cases.

Just because a person has inherited an altered gene does not mean that they will definitely develop breast cancer or other related cancers. But it does mean that they are at higher risk compared to the general population. The first step is understanding your options, one of which is the right to request genetic testing if you meet the criteria for it.