Genetic Testing

If you’re concerned about a family history of breast or ovarian cancer, you can look into genetic testing. It’s believed 5% of cancers are because of genetic mutations. Once you’ve investigated your family health history, your next step is to talk to your doctor about whether you should see a genetic counsellor and potentially get some genetic testing. Here we explore some of the questions you might have about this:

What is a genetic counsellor?

A Genetic Counsellor is able to provide information about genetics and inheritance, genetic testing (where appropriate), calculation of an individual’s cancer risk based on their family health history and/or genetic test results and a cancer risk management plan which may include screening, risk-reducing medication and/or preventative surgery. A Genetic Counsellor’s role is to provide information and support to you and your family and help you:

  • investigate a family health history
  • learn about and adjust to the knowledge of being at increased cancer risk
  • learn about genetic testing and understand results of testing, where performed
  • learn about ways to manage an increased cancer risk
  • support decision making regarding ways to manage increased cancer risks, and 
  • talk about genetic risk information with family members

When is genetic testing helpful?

In general, many family histories of breast and ovarian cancer are likely to be due to genes that current genetic testing cannot find, so genetic testing is not useful for every family. Some cancers might be due to a mutation in a hereditary gene where genetic testing is now possible. About 1 in 20 (5%) of women with breast cancer and about 1 in 7 (15%) of women with ovarian cancer, have an inherited mutation in a known high risk cancer gene, for example BRCA1 or BRCA2. Many women with a mutation will also have a family history of breast and/or ovarian cancer, although some won’t. Family Cancer Clinics in Australia use sophisticated statistical algorithms to determine the chance that a specific family history of cancer is due to a known hereditary gene.

Does the type of cancer make a difference?

Most types of ovarian cancer are of the kind (called high grade serous cancer) where genetic testing is now offered, even when there is no family history of cancer. This is because for about 1 in 7 (15%) women a genetic cause may be identified. If you’ve been diagnosed with ovarian cancer at any age, you should have a conversation with your doctor about whether you should be referred to a Family Cancer Clinic for a discussion about genetic testing.

If you have breast cancer that is ‘triple negative’ (this means where the cancer pathology report shows hormones such as oestrogen or progesterone and another protein called HER-2 do not bind to the breast cells) then we also suggest you talk to your doctor about whether a genetic assessment is recommended. This is usually considered if the cancer was diagnosed before 50 or if there is also a family history of breast or ovarian cancer. Similarly, if you’re a man with breast cancer, it’s also advised you discuss a genetic referral with your doctors. There are other situations where a breast cancer diagnosis warrants further discussion with a doctor. If you have had breast or ovarian cancer, we suggest you talk to your doctors about whether you should be referred to a Family Cancer Clinic.

What are the features of a hereditary cause of breast and/or ovarian cancer?

There are a few features of hereditary causes, these include:

  • whether a relative is already known to have had a mutation found on a genetic test
  • the number of close relatives who have had breast or ovarian cancer
  • a relative with certain types of breast or ovarian cancer
  • a relative with cancers occurring at young ages (e.g. before age 40 years for breast or before age 50 for ovarian cancer) 
  • relatives with cancer in both breasts
  • male relatives with breast cancer
  • a relative who has had both breast and ovarian cancer
  • an ethnic background from a population where some mutations are more common e.g. Eastern European (Ashkenazi) Jewish ancestry

iPrevent assesses if you have any of these factors in your family history and helps guide whether you or your family may benefit from an assessment by a Family Cancer Clinic. If you have not had cancer and have a family history of breast or ovarian cancer, you can use this tool.

The known high-risk cancer genes only explain a small proportion of family histories of breast and ovarian cancer. For some families, genetic testing may not be helpful in explaining the risk of cancer. What is still useful is a more detailed assessment of your risk of developing breast and ovarian cancer, along with advice on check-ups and ways to reduce those risks. National referral guidelines for health professionals on when to refer to genetic services are listed here

How does genetic testing affect my insurance?

Genetic testing can have an impact on the ability to obtain certain types of insurance. Private Health insurance is NOT affected. However, some other types of insurance can be affected. This is quite a complex area, and a Family Cancer Clinic will discuss this with you prior to gene testing. There is also more information that can be found here. Having genetic testing can provide helpful information but can also raise concerns and worries for you and/or other family members. Genetic Counsellors are trained to help support you and your family as you learn and communicate about hereditary cancer risk information with each other. So let them know if there is something that you’re concerned about.

What do I do if I have a family history of a hereditary breast or ovarian cancer gene mutation?

We strongly encourage anyone with a family history of a hereditary breast or ovarian cancer gene mutation to speak to their doctor or contact a Family Cancer Clinic. Attending or contacting a Family Cancer Clinic does not mean you have to have a gene test. Family Cancer Clinics can provide more information about gene testing, support you in making a decision that is right for you and provide advice about ways to manage your cancer risks. 

The location of Family Cancer Clinics in Australia can be found here.

Types of Genetic Testing

There are two types of genetic testing: mutation detection (searching) and predictive testing.

1. Mutation Detection

Mutation Detection means searching a gene to try and identify a genetic mutation (fault) in a gene that is associated with causing an increased risk of cancer. In most cases, this type of genetic testing is usually done in the person who has been affected by a relevant cancer. 

Doing gene testing this way increases the chance of finding a gene mutation. It also helps in clarifying the risk of cancer and options for gene testing for other relatives.

Genetic testing for known hereditary breast and ovarian cancer genes is usually ordered by a Family Cancer Clinic and is done via a blood sample. The result can take a few months (sometimes longer) to become available.  In some situations, the doctor can request the results be fast tracked, and is usually done where a treatment decision is dependent on the result of the test. Read more about interpreting your results. 

How much does the mutation genetic test cost?

For some families, publicly funded gene testing is available. Firstly, your family needs to meet the criteria for referral to a Family Cancer Clinic who then use the findings of their assessment to see whether publicly funded gene testing can be offered. 

Genetic testing usually begins in someone who has been affected by cancer, as this optimises the chance of finding a gene mutation. In addition, testing someone who has been affected by cancer also helps interpret the options for gene testing and the cancer risks are for other relatives. Where publicly funded gene testing is not offered, this is usually because there is a less than 10% chance of a known hereditary gene explaining the family history.

What happens if the family member affected by cancer has died?

In this situation, it is best to talk to your doctor about the family history and to see if you are eligible to seek a referral to a Family Cancer Clinic to discuss the options.

Can I just pay to get the test done?

In some situations, you may wish to pay for your gene testing privately. This is best done after speaking with a doctor or a Family Cancer Clinic. It is important to understand the chance a hereditary gene mutation causes a family history of cancer, the outcomes and potential limitations of gene testing in your particular situation. The cost of testing starts from $800 depending on the type of testing performed. There are no Medicare or private health insurance rebates available for this testing in Australia.

2. Predictive testing

Predictive testing is a type of gene testing that determines whether you have inherited a gene mutation that is already known to be present in your family. If you have inherited the gene mutation, you will be considered at an increased risk of specific cancers and there is a chance (for BRCA1 and BRCA2, this is a 1 in 2 chance) your children will have inherited the same gene mutation. 

If you haven’t inherited the gene mutation, you are usually at a lower risk of cancer. In most cases, you will have the same risk as the general person’s risk (which is not zero but is usually considered low). This also means that there is no risk of passing that particular gene mutation onto your children. Hereditary breast and ovarian cancer gene mutations, such as BRCA1 or BRCA2, can be passed down from either a Mother OR a Father. So, if the family history of a hereditary gene mutation is present on a Father’s side of the family, it is important to seek advice. 

This type of genetic testing is accessed by attending a Family Cancer Clinic. A GP can refer you to a Family Cancer Clinic. After attending the appointment, the Family Cancer Clinic will arrange for blood to be collected for the gene test. The result can take at least 4-8 weeks. In some situations, a doctor can request the results be fast tracked, and is usually done where a treatment decision is dependent on the result of the gene test. Read more about interpreting your results.

How much does the test cost?

In most cases, predictive gene testing is publicly funded.

Understanding your genetic testing results

Interpreting a gene test result is complicated. When you’ve done genetics testing, you should have your results explained by an appropriately trained medical or genetics specialist. Factors such as, whether there is a family history of cancer, whether a hereditary gene mutation is already known to be present in a family and whether the person having a test has been affected by cancer or not, are important when interpreting the meaning of a gene test result. For a more in-depth explanation of genetic testing results, read more here

Wait, I have more questions about genetic testing…

No problems, we are there for you. For more information about gene mutations and genetic testing, read our blog article ‘Common questions about genetic testing for cancer’.

To understand more about gene mutations and how they may affect your cancer risk, read more here.