Could It Be Genetic? Understanding Hereditary Bowel Cancer

Most people diagnosed with bowel cancer don’t have a family history. But for a small percentage of Australians, bowel cancer runs in the family and knowing that could save your life or someone else’s.

Hereditary bowel cancer isn’t common, but when it’s there, it often means cancers develop younger, faster, and more aggressively. It’s the kind of thing you don’t want to find out the hard way.

How Does Bowel Cancer Become Hereditary?

Hereditary bowel cancer happens when a gene mutation (faulty gene) gets passed down through families. This mutation increases the risk of developing certain cancers, often bowel cancer, but sometimes others like uterine, ovarian, stomach, or even skin cancers.

The two most well-known hereditary conditions linked to bowel cancer are:

• Lynch Syndrome (LS): Also known as hereditary non-polyposis colorectal cancer (HNPCC). The most common inherited bowel cancer syndrome.
• Familial Adenomatous Polyposis (FAP): A rare but aggressive inherited condition causing hundreds of polyps in the bowel, often from teenage years.

Red Flags That Might Suggest Hereditary Risk

Most genetic services look for a pattern like:

• Multiple family members diagnosed with bowel cancer
• Bowel cancer diagnosed before age 50
• Family history of womb (uterine), ovarian, stomach, or other related cancers
• More than one cancer in the same person
• Hundreds of polyps found in the bowel (FAP clue)
• Known Lynch Syndrome or FAP in the family

If any of this sounds like your family, it’s worth getting checked out.

What Should You Do If You’re Worried?

Your first step is a conversation with your GP. Be blunt. Tell them exactly why you’re concerned and ask directly about genetic testing or a referral to a Familial Cancer Centre.

In Australia, Familial Cancer Centres (FCC) are free services specialising in assessing your family history and organising genetic testing if needed. They can also offer advice about cancer screening, risk management, and talking to family members.

Some services include:

• Bowel Cancer Australia’s guide to genetic counselling and testing
• Family Cancer Clinics at major hospitals in every state
• Genomic testing through public hospital systems or private labs

Is Genetic Testing Free in Australia?

Sometimes yes, sometimes no. If you meet certain criteria (strong family history, early-onset diagnosis, multiple cancers), genetic testing may be fully covered through a public Familial Cancer Centre.

Private testing is available but can cost between $400 and $2,000 depending on what’s being tested. Your GP or FCC can guide you on whether you qualify for Medicare rebates or free testing.

Lynch Syndrome: The Most Common Hereditary Risk

Lynch Syndrome increases your lifetime risk of bowel cancer up to 80 percent, often before age 50. It’s also linked to other cancers like womb, ovarian, stomach, and skin cancers.

People with Lynch are usually recommended:

• Colonoscopy every 1–2 years (starting as early as age 25)
• Screening for other related cancers
• Possible preventative surgeries
• Family members tested for the same gene mutation

FAP: Rare But Serious

Familial Adenomatous Polyposis (FAP) is less common but extremely high-risk. It causes hundreds of polyps in the bowel, usually starting in teenage years.

Without treatment, bowel cancer is almost guaranteed, often before age 40. Management usually involves:

• Regular colonoscopies (often starting in early teens)
• Surgery to remove the bowel as a preventative measure
• Ongoing monitoring for other cancers
• Testing for family members, even kids

Don’t Assume You’re Safe Just Because No One Talks About It

Family silence is real. Many Aussies have no idea what cancers their grandparents or great-grandparents had, or never talked about it at all.

If you’ve got gaps in your family history, or people died young, that can actually be another red flag.

Ask questions. Dig into family history. And if no one knows, that’s still worth mentioning to your GP or genetic service.

What If You’re Diagnosed With Hereditary Bowel Cancer?

If testing shows you have Lynch Syndrome or FAP, it’s not the end of the world, but it does change things.

It means:

• You can take action early.
• Your family can get tested and screened.
• Your medical team can watch for cancers that might otherwise go undetected until it’s too late.

And yes, it can feel confronting, isolating, or even guilt-inducing. That’s normal. Genetic counsellors are there to help with that side of things too.

Australian Resources for Genetic Testing and Support

• Bowel Cancer Australia – Genetic Counselling Information
• Centre for Genetics Education – Australia
• Bowel Cancer Australia – Never Too Young Initiative
• Familial Cancer Centres – Search via your state’s public hospital system
• Your GP – First point of contact for referrals

Final Thought

If there’s even a tiny chance bowel cancer could run in your family, get it checked. Don’t sit on it. Don’t wait until it’s too late. This is one of those rare times in life where knowing for sure gives you power, not fear.

And if it turns out there’s nothing hereditary going on? Even better. But at least you’ll know for sure.