What you should know

A majority of cancers are caused by gene changes happening during our lifetime. However, some people might have an elevated risk of particular types of cancer since they were born with a gene change. These occur when there is a change in the genes in an egg or sperm cell at the time of conception. This type of gene change can pass from generation to generation, known as germline mutation.

Having said that, being born with inherited gene changes doesn’t necessarily mean the person will get cancer. However, they will carry a higher risk of developing certain types of cancer than other people. They are also more likely to develop cancer when relatively young. This is called having a genetic predisposition to cancer. But for cancer to develop, more gene changes must occur, which could take years.

Cancers from inherited gene changes are much less common than those due to gene changes caused by other factors. Most cancers develop from a combination of chance and the environment, and not because of any specific cancer gene we inherited. Genetic scientists peg cancers linked to an inherited gene change at just 12% of all cancers diagnosed.

Why is family history important?

This is just one part of the story. However, knowing your family’s medical history is the initial step towards comprehending your cancer risk. Based on that, your doctor can advise certain screening tests and also guide you regarding any genetic counselling or testing you might require.

Being aware of the family history can help healthcare personnel to prescribe adequate preventive measures and lifestyle modifications that can actually delay or even prevent the development of certain cancers, including the hereditary ones. Family history can also provide valuable inputs for treatment strategies in those diagnosed with cancer.

The relevance of your family history hinges on:

Who in your family has a history of cancer
The types of cancer they have had
At what age they were diagnosed
How close the relationship between cancer-stricken relatives is

Indications of a strong family history include these situations:

Family members had cancer when they were relatively young, for instance, below 50 for breast, bowel and womb cancer
Two or more relatives, either on the mother’s or father’s side, have had uterine, breast or colorectal cancer
Relatives developed the same type of cancer or different cancers that can be precipitated by the same genetic flaw
One of the relatives has had a gene change discovered through genetic tests

What is genetic counselling?

If your family history indicates a higher cancer risk, you might be advised to go for genetic counselling. A genetic counsellor will enquire about your family history and based on those inputs, decide if you need genetic testing. Done from saliva or blood samples, a genetic test looks for changes in the DNA, often called mutations, to determine if you have a higher risk of developing cancer than others.

If you have a genetic mutation, it doesn’t necessarily mean you will get cancer. You can ask your doctor about screening tests, medication or surgery to lower your cancer risk and about making healthy lifestyle choices like quitting smoking, cutting down on your drinking, exercising regularly and managing your diet and weight better.