Genetic testing is the scientific testing of a person's genes. It is usually done when someone is at an increased risk of inheriting a changed gene .
Genetic testing can determine whether you have inherited a high risk of cancer. For example, if a genetic test finds that you have a fault in the BRCA1 or BRCA2 genes, you likely have a higher risk of developing breast or ovarian cancer. It does not mean that you will definitely develop the disease.
Genetic testing will be discussed with you at your appointment at a familial cancer centre and is only offered with genetic counselling. This is because it is important to talk about the limitations and potential benefits of genetic testing with health professionals so that you can make an informed decision.
Eligibility for genetic testing
Genetic testing is only appropriate for a small number of families referred to familial cancer centres. Eligibility for genetic testing is based on family history and other criteria and is assessed independently for each family.
The process usually starts with testing a family member who already has a specific type of cancer and involves taking blood. If the changed gene causing the cancer is found, testing may be offered to other family members.
It is also important to note that some changed genes may not be picked up using existing technology.
Learning about your family history of cancer and inherited risk can be overwhelming. You may experience a range of emotions. Call 13 11 20 to speak to our compassionate cancer nurses or join our online community and connect with other people who have a similar experience.
You may also want to listen to The Thing About Cancer podcast episode on genetic tests and cancer .
There are many important medical, ethical, social and legal issues to be considered before having genetic testing. These can be discussed with a genetic counsellor. You will have counselling before and after genetic testing.
All familial cancer centres employ genetic counsellors who can:
- provide information, support and counselling to individuals and families
- clarify your risk of having inherited a changed cancer gene based on your family history
- discuss what management plans may be appropriate
- discuss the limitations, potential benefits, disadvantages and appropriateness of genetic testing.
Genetic counsellors work with a multidisciplinary team of specialists at familial cancer centres, including clinical geneticists (medical doctors with a specialty in genetics), oncologists, surgeons and gastroenterologists, among others.
Considering genetic testing
How much a genetic test can help depends on:
- how accurately a test can predict the level of risk
- if there's a high risk, whether anything can be done to lessen it
- whether anything can be done that's seen to be useful by the person being tested.
Genetic specialists will help you understand the risk and benefit of undergoing genetic testing. Depending on your situation, they may help you consider the following outcomes:
Possible benefits for those found to carry a changed gene
- Testing can reduce uncertainty about whether you have a higher risk of developing cancer than the general population.
- You can get a more accurate estimate of your risk than you can get from just looking at your family history.
- You can learn what risk your children have of carrying a changed gene. You can then help advise your children about whether they should also be tested.
- You can make more informed decisions about family planning, such as getting pregnant and having foetal testing.
- You'll be better advised regarding surveillance and prevention.
Possible disadvantages for those found to carry a changed gene
- You may feel anxious, afraid or depressed about your current situation and your future.
- If you have children, you may feel anxious and guilty that they're at a higher risk of developing cancer.
- Making decisions about having children in the future may become more complex and difficult.
- Family relationships can be put under strain.
- You may be uncertain and feel worried about the impact your test result may have on your finances, including your employment, superannuation and life insurance.
- You may feel anxious about whether your test result could be misused, now or in the future.
Possible benefits for those found not to carry a changed gene
- No more uncertainty for you or your children about your risk of developing cancer, which is now about the same as the general population.
- You will not need to undergo unnecessary extra surveillance.
Possible disadvantages for those found not to carry a changed gene
- You may feel guilty that you've been ‘spared’, while others in the family remain at risk.
- Family relationships can be put under strain.
- You may feel a loss of identity.
- You may not fully believe the test results and continue to worry about your risk.
More information on genetics and risk
A range of organisations provide information and support specifically for people concerned about their family history of cancer. You may find the following helpful:
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The information on this webpage was produced by Cancer Council Victoria (2022). This webpage was last updated in February 2022.