Should I Get Genetic Screening?

It’s hard enough planning retirement around the things we can control, but what about the things we can’t? Everyone hopes they have enough money to see them through a long happy retirement with a comfortable lifestyle, but what about the unforeseen events that can get in the way? Unwelcome surprises come along throughout all times of life (financial, personal and health issues), but in retirement they can seem to appear at an alarming rate. If you had a crystal ball, would you want to know what’s coming so you can be prepared, or would you prefer blissful ignorance? Specifically, would you want to know if you are at higher risk of developing certain types of cancer?

It’s not an easy question. About 5% to 10% of all cancers are thought to be related to gene mutations that are inherited or passed down through the family. Predictive genetic testing can look for inherited gene mutations, and is recommended when a gene mutation is suspected. This may be because of identified risk factors, including:

• You have several first-degree relatives (mother, father, sisters, brothers, children) with cancer.
• Many relatives on one side of your family have had the same type of cancer.
• There are clusters of cancers in your family, such as breast, ovarian, colorectal, and pancreatic cancers
• A family member has more than 1 type of cancer.
• Family members have had cancer at younger than average for that type of cancer.

Genetic testing is also done to determine whether family members without obvious illness have inherited the same mutation as a family member who is known to carry a cancer-associated mutation.

Testing is done on a small sample of body fluid or tissue—usually blood, but sometimes saliva, cells from inside the cheek, skin cells, or amniotic fluid (the fluid surrounding a developing fetus). Samples are analysed in a laboratory that specializes in genetic testing, and returned to the treating doctor after several weeks.

A “positive test result” means the laboratory found a specific genetic mutation associated with a hereditary cancer syndrome, and may:

• Provide early diagnosis of a hereditary cancer syndrome
• Show that someone carries a particular genetic change that does not increase their own risk of cancer but that may increase the risk in their children
• Suggest a need for further testing
• Indicate an increased risk of developing certain cancer(s) in the future. If this is the case, you can take steps to lower that risk, or increase the likelihood of early detection through regular checkups, preventative medication or surgery, lifestyle changes.

Genetic tests can’t tell you whether you will or won’t get cancer, only if you have a higher risk. “Negative test results” mean the laboratory did not detect the specific mutation. This does not mean that there is no cancer risk, but rather that the risk is the same as the cancer risk in the general population.

While early detection of cancers can help keep you and your family members free of cancer or increase the success of treatment, there are some downsides to consider.

• Tests are expensive and aren’t always accurate.
• Results can lead to more tests, waiting time, anxiety and costs
• Genetic tests can reveal information not only about the person being tested but also about that person’s relatives. Family relationships can be affected when one member of a family discloses genetic test results that may have implications for other family members.
• Knowing that you are at risk can lead to feelings of fear and guilt for family members.
• The possibility that a test result might not be informative—that is, that the information may not be useful in making health care decisions.

Before undergoing any genetic testing, seek advice from a genetic counsellor, who will work through the likely benefit and reliability of any tests, as well as possible consequences.

If you had a crystal ball, would you want to know what’s coming so you can be prepared, or would you prefer blissful ignorance?