Bowel Cancer is on the Rise in Young Australians: What You Need to Know

Written By Jessica Stuart-Harris

Some Uncomfortable Numbers

  • Bowel cancer is now the deadliest cancer for Australians aged 25–44 years.

  • Those born after 1990 face double the risk of colon cancer and quadruple the risk of rectal cancer compared with people born in 1950. 

  • The risk of being diagnosed with bowel cancer before age 40 has more than doubled since the year 2000. 

  • Bowel cancer rates have increased by 266% in adolescents and young adults (15-24 years) over the past three decades.

Common Symptoms of Bowel Cancer

  • Blood in your stool or rectal bleeding: This may appear as bright red blood in the toilet bowl or on the toilet paper or darker, tarry-looking stools.

  • Persistent changes in bowel habits: Diarrhoea, constipation, or a feeling that your bowel doesn’t empty completely.

  • A change in stool shape (e.g. narrower than usual).

  • Unexplained weight loss: Losing weight without trying can be a red flag for many conditions, including bowel cancer.

  • Abdominal pain, cramping or bloating, especially if it’s ongoing and doesn’t seem linked to diet or other common causes.

  • Fatigue and weakness, often caused by internal bleeding leading to iron-deficiency anaemia.

  • A lump or swelling in the abdomen or rectum. This could be a sign of a tumour or advanced disease.

When to See a GP

You should speak with your GP if:

  • You have any of the symptoms above lasting more than 2–3 weeks

  • You notice blood in your stool, especially if it happens more than once

  • You have a family history of bowel cancer

  • You’re under 50 and are being told your symptoms are likely “nothing”

Early detection is key. Many of these symptoms can also be caused by less serious conditions (like haemorrhoids or irritable bowel syndrome), but it’s important to rule out something more serious.

The Myth: “You’re Too Young”

One of the issues many patients report is being told they’re “Too young” to have bowel cancer — a misconception that can delay diagnosis for months or even years.  This means that by the time they receive a diagnosis, the disease is far more advanced and less likely to be cured.

Why the increase in bowel cancer in young people?

We do not know the exact reason why there is such a frightening rise in the rate of bowel cancer in young people, but we think there are some significant associated factors.  These include:

  • Increased rates of obesity

  • Increased rates of diabetes

  • Smoking

  • Increasingly sedentary lifestyle

  • A change in the gut microbiome

  • Increased antibiotic use in childhood

  • Changes to how humans get their foods, including pesticides and microplastics.

  • Poor diet high in processed foods, red meat and low in fibre

  • High alcohol intake

A possible theory is that the factors above can change gut bacteria, disrupt gut function, promote inflammation, and elevate cancer causing agents in the colon.  Genetic factors account for 20% of early onset cases; the other 80% is thought to relate to the factors above.

So, what does this mean? How should we respond to this?

  • Bowel Cancer Australia has created the “Never2Young” program which aims to educate the community and doctors about bowel cancer.  They have succeeded in reducing the federal screening age via the mailout bowel kit from 50 to 45 years. GPs can request some patients start at 40 years if they have particular risk factors.

  • Further research into bowel cancer and its management.

  • Know the danger signs and symptoms or RED FLAGS and talk to your GP about a referral for a colonoscopy if they are present.

  • Support Bowel Cancer Australia and their Never2Young movement.

What are the RED FLAGS? 🚩

  • Blood in your stool

  • Change in bowel habit

  • Abdominal pain

  • Fatigue

  • Low blood cell count or iron level

References

1.      Bowel Cancer Australia. https://www.bowelcanceraustralia.org/bowel-cancer/early-onset/ [06/06/25]

2.      Liotta, M. News GP: RACGP: News GP: Why are more young people getting bowel cancer?

3.      Australian Institute of Health and Welfare: Cancer Data in Australia. https://www.aihw.gov.au/reports/cancer/cancer-data-in-australia/contents/cancer-data-commentaries/an-overview-of-colorectal-cancer-in-australia [06/08/25]

Jessica Stuart-Harris
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