Family history
If any of your family members have bowel cancer, you might be worried about your chance of getting the disease. However, bowel cancer is common and in most cases it's not passed down through the family.
Some bowel cancers are caused by a change in one or more genes. A gene change may also be called a mutation, variant, gene fault or gene error. These gene changes can be passed down through a family. If you have one of these gene changes, you may have a higher chance of getting bowel cancer at some point in your life.
Around 5-10% of all bowel cancer cases are thought to be caused by a change in a known gene. The changed gene can be passed down through a family. If you have the changed gene, you may have a higher chance of getting bowel cancer at some point in your life. We don't yet know all of the genes that affect the chance of developing bowel cancer.
The genetic conditions we know about include:
People with these conditions have a much higher chance of getting bowel cancer and they’re more likely to be diagnosed at a younger age.
Family history of bowel cancer
Your chance of developing bowel cancer may be higher if you have a family history of the disease. This means that a close relative (parent, sibling or child) has been diagnosed with bowel cancer. Doctors may also call these relatives 'first-degree relatives'.
Talk to your GP if you have more than one close relative diagnosed with bowel cancer, or if a close relative is diagnosed under the age of 50. They might refer you for genetic testing to see if you have a higher chance of developing bowel cancer.
Genetic testing
Genetic testing looks for changes in different genes. If you're offered genetic testing, you'll be given information about the test and how to results might affect you and your family. You can then decide if you want to have genetic testing or not.
If genetic testing shows you have an inherited condition linked to bowel cancer, your family members may also be offered testing to see if they carry the same changed gene. If they do carry the gene change, they’ll be offered regular bowel screening. If your relatives don’t want to have a genetic test, they can still have regular screening if they have a 1 in 2 (50%) chance of carrying the changed gene.
In most cases, bowel cancer is not caused by an inherited condition, so genetic testing of family members isn’t needed.
Tell your GP if you have:
- a close relative (parent, sibling or child) diagnosed with bowel cancer before the age of 50 years
- two or more close relatives diagnosed with bowel cancer at any age (for example your parent, and their sibling or parent)
- a relative with a known genetic (inherited) condition linked to bowel cancer, such as Lynch syndrome or familial polyposis
If you’re planning to start a family, you may have questions about the risk to your children. Your genetics team will be able to answer these. They will also be able to discuss other fertility options with you. The Human Fertilisation and Embryology Authority have more information about options available to you.
Questions to ask
- Can I have genetic testing?
- Have I had genetic testing?
- What type of genetic testing have I had?
- Do my family members need to be tested?
- Who do I need to tell in my family?
Updated: September 2025
Next review: September 2028
For more videos on genetic conditions that are linked to bowel cancer, please visit our YouTube channel.
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