Cancer Research UK on Google+ Cancer Research UK on Facebook Cancer Research UK on Twitter

Before you decide to have a gene test

This page has information about what you need to think about before deciding to have a gene test for cancer. There is information on


The pros and cons of genetic tests

You may be aware of people having genetic tests for cancer and it may seem quite straightforward. But as is often the case, it is more complicated than it seems.

Firstly, tests have to be for a particular type of cancer, not just cancer in general. There may not be a test for the type of cancer you are worried about. Tests are currently only available for a few genes. You can read our information about inherited genes that doctors can test for.

Gene testing is a fast moving and constantly changing area of medicine. It is likely that tests for more genes will become available within the next few years.

Even if there is a test available, it isn’t straight forward. For testing on the NHS, you need to have a family history of cancer. Generally speaking, this means at least 2 close family members with the same cancer type.

It would be too time consuming and expensive to look for a gene fault until the specialists have some idea of the type of fault to look for. Even if you’ve had cancer yourself, it helps considerably if the lab knows which type of gene fault they are trying to find.

If you have a living relative who has had cancer, they can have a test to see if they have a faulty gene. But of course they have to be willing to be tested. This isn’t always an easy decision.

If a relative has already had a test and has a faulty gene, the lab staff can look for exactly the same gene fault in your genetic code. So they can tell you whether or not you have inherited the same one.

Unfortunately, it can still be difficult to find a gene fault. There are many different gene mutations. The genetic code is very long and a gene fault could be in many different places. Doctors will be more able to find a faulty gene if you have a living relative they can test. But even this is not 100% accurate.


How reliable is gene testing

Genetic tests are very reliable if they are looking for a cancer gene that is known to run in a particular family and has been identified in a relative. 

Sometimes a family can have a strong history of cancer without any known faulty cancer genes showing up on a test. This could mean that the family has a gene fault that scientists haven’t identified yet.

There is information in this section about what it means if the test doesn’t find a faulty gene.


The likelihood of a cancer gene in the family

Before you can have a test, your doctor needs to work out if you have a strong enough family history for a referral to a specialist genetics clinic.

Remember that having one person in your family who has had cancer doesn’t mean that there is a cancer gene running in your family. It depends on the circumstances. Cancer is a common disease. 1 in 2 people in the UK (50%) will get it at some point in their lives. And it is more common with increasing age. So having more than one elderly relative diagnosed with cancer does not necessarily mean there is an increased cancer risk in your family.

You can read about what a family history of cancer means.


If you can’t have a test

Some people's family history means that a gene test is not suitable. This is most likely because you don't have a strong family history. If you have a family history of breast or bowel cancer and a gene test is not suitable your specialist may suggest you have screening. You can find out more about this in the screening section for each cancer type.      

If you are worried that you may have an increased risk, you could talk to your doctor. 

You can print out and take along our questions for your doctor.

There are many things you can do to reduce your risk, such as

  • Not smoking
  • Eating a healthy well balanced diet
  • Exercising regularly
  • Keeping to a healthy weight

We have information about healthy living that tells you how to reduce your cancer risk.


Why some people decide not to have the test

Not everyone who goes to a genetics clinic has a test. Some people choose not to. After thinking it through, some people decide that they don’t want to know if they have a higher than normal cancer risk. Some people decide they don’t want any preventative treatment even if they have a faulty gene. So they may not feel they have anything to gain by having the test.

Only you can decide what is best for you. The emotional effects section includes some questions worth thinking about before you decide.

If your GP refers you to a specialist clinic, your first appointment will include working out what your risk is, then helping you to decide how to deal with it. You may find you aren’t at any more risk than the average person.


What happens if the result is positive

Before you have a test, the genetic counsellor will talk to you about what your options are if you do have a faulty gene. It is usually part of the process of deciding whether to have the test or not. What you decide to do next depends on

  • The gene that you have
  • Which cancer(s) you are at increased risk of developing
  • Your age and plans for the future

Your options may include

  • Screening
  • Treatment to reduce your risk

There is more information about the options in the getting the results of tests page.


Emotional effects

Making a decision about whether to have gene testing isn’t easy. It is normal to feel anxious. Thinking about the possibility of getting cancer is difficult. It may also stir up emotions you felt when other family members were diagnosed with cancer and what they went through.

There is no rush. Take time to think it through. Before you decide, it can help to think about these questions

  • How do you feel about having a test?
  • What will the result really mean for you and your family?
  • What will you do if the result is positive?
  • How will you feel if the result is positive?
  • Will you feel reassured by a negative test?
  • Would you rather not know?
  • Is there treatment to reduce your risk?
  • If there is treatment, would you consider having it?
  • What will happen if you decide not to have the test – could you have screening?

Remember it is your decision, but talking with your family and knowing how they feel may help you to make the decision. There is more information about how it may affect your family on this page. If you decide to go for testing and you have a strong family history you will be supported by a team of specialists. You will be offered genetic counselling and you can change your mind at any time if you decide not to have a test. 

Children cannot usually be tested. This is because anyone having a genetic test needs to be old enough to make their own choice about whether to have the test or not. They also need to be able to fully understand all the different effects that having the test might have on them and their family members. The exceptions to this are for genes that can cause cancer at a young age and for which there is screening that works well. These include

  • Familial adenomatous polyposis (FAP)
  • Retinoblastoma (RB1)
  • Multiple endocrine neoplasia (MEN)

Effect on your family

Most people looking into their family history need to talk to their relatives to find out who has had what type of cancer and when. This is not always as easy as it may seem. Finding out about your family history can be a very emotional time for everyone.

Even if you want to find out more about it, your relatives may not want to discuss it, or may not feel emotionally strong enough. This can cause difficulties in some families. For some people it may raise issues that haven’t been spoken about before, or not for a long time. Talking to a counsellor can help you think about all the issues and find ways of coping with them.

Even if you don’t need to speak to relatives, it is worth thinking about what you want to do and who you will tell once you know the result. Again talking with a counsellor can help you work this out.


Financial considerations

Many people are concerned about getting health and life insurance after having a genetic test. Currently the Association of British Insurers (ABI) and the Government have agreed to a temporary ban on asking people for the results of genetic tests for cancer. This agreement is called a Concordat and Moratorium. The agreement lasts until 2017 when they will review it.

Insurance companies can still ask about family history and may charge more for families with a strong family history of cancer. If you have had a genetic test and it shows that you don’t have a gene, you may choose to tell the insurance company.

The Human Genetics Commission used to be responsible for making sure that insurance companies follow the agreement. The responsibilities of the HGC have been taken over by the Emerging Science and Bioethics Advisory Committee (ESBAC).This Government committee will work with the Government and the Association of British Insurers to work out what happens after 2017.  If you have had any problems with an insurance company that you can't sort out, you can complain to

There is information about mortgages, pensions, loans and insurance for people with cancer in our coping with cancer section.

Rate this page:
Submit rating


Rated 5 out of 5 based on 6 votes
Rate this page
Rate this page for no comments box
Please enter feedback to continue submitting
Send feedback
Question about cancer? Contact our information nurse team

No Error

Updated: 27 March 2015