Bowel cancer can be inherited

Genetic mutations have been identified as the cause of inherited cancer risk in some bowel cancer–prone families, and these mutations are estimated to account for 5% to 10% of bowel cancer cases overall.

Lynch syndrome (HNPCC) is the most common genetic condition that increases a person’s risk of developing bowel cancer and is caused by a change in a gene that normally functions to protect a person from getting cancer.

Where a person has inherited the HNPCC genetic mutation, the lifetime risk for bowel or other syndrome cancers is 70-90%.

In families where there is a clear history of HNPCC, screening with colonoscopy every 1 to 2 years usually commences from age 25 or 5 years earlier than the youngest affected family member if they were diagnosed under 30 years, whichever comes first.

Lynch syndrome has preventative health and screening implications for family members and can also affect the best choice of treatment options for bowel cancer patients.

Bowel Cancer Australia continues to encourage all Australians to better understand their bowel cancer family history and for all newly diagnosed patients to speak with their treating specialist about having their tumour tested for mismatch repair deficiency as a means to subsequently identify Lynch syndrome.

If you have been diagnosed with bowel cancer, ensure your treating specialist performs the test that could help determine if your cancer may have been genetically inherited.

Where HNPCC is suspected, your GP will refer you to a Family Cancer Clinic (Genetic Counsellor) for support and ongoing management of the condition.

For further details download our Non-modifiable Risk Factors and Screening & Surveillance booklets or read more about Lynch Syndrome and Genetic Counselling on our non-modifiable bowel cancer risk factors webpage.

Start the conversation

Inherited Cancers Awareness Day (ICAD) is a national awareness campaign led by Inherited Cancers Australia each year on 27 August.

The 2026 campaign focusses on starting the conversation about inherited cancers, and what that might mean to you, your family or someone you support.

That conversation might be about (bowel) cancer in your family, symptoms you are worried about, a diagnosis, genetic testing, or questions you are not sure how to ask.

Talk to family if you can, or speak with your GP, a genetic counsellor or contact Bowel Cancer Australia’s Specialist Support Services team.

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We’re here for you

Bowel Cancer Australia’s specialist support services are uniquely designed for you, whether you have questions about bowel cancer and your personal risk, or are living with or beyond bowel cancer, and for your family and friends.

You can email, call or video chat with one of our friendly Bowel Care Nurses, simply submit your support request online here or call 1800 727 336.

Christine’s story

“27/4/18 is the day my world was turned upside down. A strong family history of bowel and ovarian cancer lead to genetic testing and positive result I had Lynch syndrome.

This day was my first surveillance colonoscopy which revealed Stage 3 bowel cancer – I had no symptoms! I was 29, far younger than my father (bowel cancer age 50), grandmother (ovarian cancer age 50, bowel cancer to follow) and great grandmother (bowel cancer) were.

I had a total colectomy and then three months chemo via a port-a-cath. The following year I had a preventative hysterectomy including ovaries at age 30. I now have an annual sigmoidoscopy (as I no longer have a colon) and endoscopy, and so far all results have been good. My first surveillance colonoscopy’s timing saved my life!” ~ Christine.

Read more lived experience stories here.

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“The most important part of what we do is to be person focused – in genetics we extend this to the family.”

In this episode of The Bottom Line Podcast, highly regarded Geneticist, Professor Ingrid Winship AO discusses the dynamic world of genomics and how a genetic test may impact you and your family.

Drawing on her decades of experience Professor Winship provides practical information to help unpack the complexities of genetics that empowers people to make informed decisions.

“What we do is about empowering people, trying to prevent predictable complications and keep healthy people healthy and genomics, genetic testing, genetic counselling, risk assessment and risk management are the cornerstones of that kind of preventative strategy.”

Professor Winship discusses approaching genetics in a wholistic way and the importance of informed consent and the role genetic counsellors play in ensuring everyone understands and is comfortable with the process.

Listen now at bowelcancerpodcast.org or wherever you usually get your podcasts.