Genetic testing for breast/ovarian cancer risk
Types of genetic testing
There are two types of genetic testing.
- Mutation detection (searching)
- Predictive testing
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 a person who has been affected by a relevant cancer. Doing gene testing in this way increases the chance of finding a gene mutation and assists 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 and is given to the person having the test by a Family Cancer Clinic or the doctor who has arranged the test. 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.
When is gene testing helpful to do?
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 generally use sophisticated statistical algorithms to determine the chance that a specific family history of cancer is due to a known hereditary gene.
The type of cancer makes a difference to the chance of a hereditary cause?
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. So if a woman has ovarian cancer at any age, we would suggest she has a conversation with her doctor about whether she should be referred to a Family Cancer Centre for a discussion about genetic testing.
If a woman has 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 she talks to her doctor about whether a genetic assessment is recommended. This is usually considered if the cancer was diagnosed before 50 or if there is also have a family history of breast or ovarian cancer. Similarly, any man with breast cancer is also advised to discuss a genetic referral with his doctors. There are other situations where a breast cancer diagnosis warrants more discussion a doctor see below.
If a woman has had breast or ovarian cancer, we suggest she talks to your doctors about whether she should be referred to a Family Cancer Clinic.
Features of a hereditary cause for a family history of breast and/or ovarian cancer
- 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
The Know Your Risk tool assesses if a woman has any of these factors in her family history and helps guide whether that woman or her family may benefit from an assessment by a Family Cancer Clinic. If a woman has not had cancer and has a family history of breast or ovarian cancer she can use this tool.
Because the known high risk cancer genes only explain a small proportion of family histories of breast and ovarian cancer, there are many families where genetic testing may not be helpful in explaining a risk of cancer. What is still useful is a more detailed assessment of a woman’s 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 on the website www.eviq.org.au.
How much does the test cost?
For some families publically funded gene testing is available. Firstly a 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 a person who has been affected by cancer also helps in interpreting and what the options for gene testing and the cancer risks are for other relatives.
Where publically 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 best person to offer gene testing or all of my family members with cancer to have died?
In this situation, it is best to talk to your doctor about the family history and to see if you are eligible seek a referral to a Family Cancer Clinic to discuss the options.
Can I pay for the test?
In some situations, people may wish to fund the cost of gene testing. 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 costs start from $800 depending on the type of testing performed. There is no Medicare or private health insurance rebates available for this testing in Australia.
Other things to consider
Genetic testing can have an impact on the ability to obtain certain type of insurance. Private Health insurance is NOT affected. However some other types of insurances can be affected. This is quite a complex area and a Family Cancer Clinic will discuss this with a person considering having a gene testing. There is also more information that can be found here.
Having genetic testing can provide helpful information for a family, but can also raise concerns and worry for the person having the test and/or other family members. Genetic Counsellors are trained to help support people and their families as they learn and communicate about hereditary cancer risk information with each other.
Predictive testing is a type of gene testing that determines if a person has or has not inherited a gene mutation that is already known to be present in a family.
If the person has inherited the gene mutation, they 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) their children will have inherited the same gene mutation.
If the person has not inherited the gene mutation, they are usually at a lower risk of cancer. In most cases people 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 to passing that particular gene mutation onto their 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 person attending a Family Cancer Clinic. A GP can refer a person to a Family Cancer Clinic. After attending an 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 to become available and is given back to you by a Family Cancer Clinic or the doctor who has arranged the test. 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.
How much does the test cost?
In most cases, predictive gene testing is publicly funded.
Other things to consider
Genetic testing can have an impact on the ability to obtain certain type of insurance. Private Health insurance is NOT affected. However some other types of insurances can be affected. This is quite a complex area and a Family Cancer Clinic will discuss this with a person having a test prior to gene testing. There is also more information that can be found here.
Having genetic testing can provide helpful information for people, but can also raise concerns and worry for the person having the test and/or other family members. Genetic Counsellors are trained to help support people and their families as they learn and communicate about hereditary cancer risk information with each other. So let them know if there is something that you are 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 about this or contact a Family Cancer Clinic. Attending or contacting a Family Cancer Clinic does not mean a person has 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, whilst you are deciding about gene testing, if you decide not to have a gene test or after gene testing.
Location of Family Cancer Clinics in Australia can be found here.