Creating a comprehensive family history involves carefully documenting each member of both your mother’s and father’s family and outlining any cancers they may have been diagnosed with and at what age. Where relevant, it may also be important to describe the outcomes of their cancer diagnoses. Lynch Syndrome Australia has developed a Family Cancer Tree tool which may assist you in this process.
N.B: If you have had a Lynch syndrome-associated cancer before you were 50 years old then, regardless of your family history you should insist on being referred to a genetics service to discuss whether you might have Lynch syndrome. Although it is best practice for every bowel cancer or endometrial cancer tumour in patients under 50 to be sent for testing, unfortunately, this does not happen every time.
If it is decided that genetic testing is appropriate, you will be referred to the familial cancer service (which may be public or private) in your state. At your initial appointment you will meet with a genetic specialist (counsellor) who has expertise in Lynch syndrome. Genetic counsellors assist you and your family to understand the genetic testing process and support your decision making throughout the testing.
If you decide to go ahead with genetic testing, a DNA sample (blood or otherwise) will be collected and analysed in a laboratory. Your results will either come back as:
The genetic test did not find a known Lynch syndrome mutation in your genes. Your genetic counsellor may tell you that this means you don’t need to follow a specific surveillance regime and your children will not need to tested.
The genetic test found a known Lynch syndrome mutation in your genes. Additional family members may now be offered predictive testing to find out whether they too have Lynch syndrome (i.e. the same genetic mutation).
A mutation was identified in your genes however it is not yet known whether it results in you having an increased chance of developing cancer in your lifetime (i.e. it is not clear whether you have Lynch syndrome). Your geneticist and/or genetic counsellor will discuss this further with you.
If you receive a diagnosis of Lynch syndrome, you will be told which of the genes is mutated in your family. If you do not, it is important to ask because your gene variant can affect your chance of developing cancer and therefore the surveillance management you will need to undertake.
This is important as it gives family members the opportunity to learn whether or not they too have a greater chance of developing cancer in their lifetime. This knowledge means that they can reduce that risk by undertaking preventative measures and engaging in their own surveillance plans aimed at detecting cancer at an early stage and before it becomes life-threatening.