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Genetic Testing and Genetic Counselling

Genetic Testing for Cancer Risk

Some people have an inherited gene fault (mutation) that can increase the risk of developing certain types of cancer.  Tests are available that look for specific inherited faulty genes or that look at a number of different genes at the same time. This is called a gene panel test. 

Testing for genes that increase the risk of cancer is called predictive genetic testing. A positive result means you have an increased risk of developing cancer. But it doesn’t mean that you have cancer or will definitely develop it.

Advantages of Genetic Testing

There are things an individual can do to reduce your risk of developing cancer if you are found to have a gene fault. For example, the person might be able to:

  • make certain lifestyle changes
  • have regular screening to detect cancer early
  • take medicines to lower the risk of developing the cancer
  • have risk reducing surgery

 Disadvantages of Genetic Testing

Some genetic test results identify a variation in a gene. But it may not be clear whether it increases a persons cancer risk or not. This can be difficult to cope with.

It can also lead to people having a constant worry about developing cancer if the test finds a faulty gene. If the test is positive, the person may also need to tell other relatives that they may have inherited the same gene.

Cancer Genetic Testing and Children

Children under the age of 18 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 understand the possible benefits and risks that having the test might have on them and their family members.

The exceptions to this are tests 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).
  • Li-Fraumeni Syndrome (LFS).
  • Von-Hippel Lindau (VHL) syndrome.
  • hereditary Leiomyomatosis. 
  • Peutz-Jeghers syndrome (PJS).
  • Juvenile polyposis syndrome (JPS)

Genetic Counselling

People who have an inherited genetic predisposition may benefit from Genetic Counselling.  Counsellors help families understand their personal and/or family history of cancer, they evaluate the probability of hereditary cancer susceptibility in individual families, and coordinate genetic testing for individuals who choose this option.

Anyone with questions about their potential risk of developing cancer may benefit from genetic counselling. 

Genetic counselling is helpful for individuals with more than one family member with the same or related types of cancer (e.g. breast and ovarian cancer or colon and uterine cancer), personal and/or family history of early-onset cancer, personal and/or family history of rare cancers (e.g. male breast cancer or fallopian tube cancer), personal and/or family history of more than one cancer in the same individual and a close relative found to have a mutation in a cancer gene.