Genetic Testing

While most cancers are not caused by an inherited mechanism, there are a small number of families that may have a higher incidence than expected of a particular cancer.  In some cases this may be explained by an identifiable inherited factor.  A genetic test may be able to clarify this.

Genetic risk assessment

Genetic risk assessment is usually done prior to genetic testing. Genetic risk assessment is the evaluation of the patients' personal risk for cancer, based on family medical history. Genetic risk assessment is done by a genetic counsellor and includes discussions about patients' family history of cancer and recommendations for future action. Genetic testing that can identify if there is a gene mutation may follow genetic risk assessment.

What is Genetic Testing?

Gene testing involves examining a person's DNA (typically taken from cells in a sample of blood) for a mutation that flags a disease or disorder. Some genetic tests can identify changes in whole chromosomes. Others examine short marker stretches of DNA within or near genes. Yet others look for the protein products of genes.

Genetic testing enables researchers to identify changes within genes that may help diagnose existing diseases, identify people who are at risk of getting a disease before any symptoms appear, predict the future development of specific diseases, or, someday, make it possible to treat or even ward off disease. Genetic tests serve many purposes. They are widely used to screen newborns for a variety of disorders.

An accurate gene test can tell if a mutation is present, but that finding does not guarantee that disease will develop. For example, a test which is positive only indicates that the risk is high but not absolute and a negative test does not exempt the person from the risk of developing cancer over time.

In spite of the above, gene testing offers several benefits - A negative result can create a tremendous sense of relief and may eliminate the need for frequent checkups and tests that are routine in families with a high risk of cancer. Even a positive result can relieve uncertainty and allow a person to make informed decisions about the future. A positive result can also let a person take steps to reduce risk before disease has a chance to develop.

Should I undergo Genetic Testing?

The decision to undergo testing is a very personal one, and experts stress that it should be totally voluntary.

After receiving genetic counselling, a person should agree to the test only if she or he wants the information, not to accommodate relatives, health care providers, or anyone else. An important consideration to weigh is this: If the results are positive, are there available methods for state-of-the-art early detection, prevention and/or treatment?

The role of Genetic Counsellors

Genetic counsellors are specially trained health professionals who are skilled at supporting individuals when testing is being considered, when test results are received, and during the weeks and months afterward. Genetic counsellors play a vital role.

Individuals whose family history indicates the likelihood of an inherited predisposition to cancer may be referred to a family cancer clinic or genetics service for risk assessment, genetic counselling, genetic testing (if appropriate), identification of other "at risk" relatives and advice about prevention, cancer screening and early detection.

Referral Procedure for Genetic Testing

Patients need to have a referral from a medical practitioner in order to be seen at a family cancer clinic or genetic counselling service. If further management is required after testing, the patients will be referred back to the General Practitioner.

For more information on Family Cancer Services at Northern Sydney Health or to make an appointment please click on the following link  Royal North Shore Family Cancer Services (130KB)