Bowel cancer awareness month by Dr Mike Hanson

June 3, 2024

Bowel cancer, also known as colorectal cancer, develops from the inner lining of the bowel and is usually preceded by growths called polyps.
An estimated 15,300 people were diagnosed with bowel cancer in 2023, making it the fourth most commonly diagnosed cancer in Australia.

Risk factors for bowel cancer

The risk of developing bowel cancer increases from the age of 50. Bowel cancer risk is increased by smoking, eating a diet low in fibre, high red meat consumption especially processed meat, drinking alcohol, and being overweight or obese.

Family history also influences bowel cancer risk, as does inflammatory bowel disease such as Crohn’s disease.


During the early stages, most patients have no symptoms and so screening over the age of 50 is very important. Symptoms can include:

  • Blood in the stool/rectal bleeding
  • A recent, persistent change in bowel habit, especially if severe (including diarrhoea, constipation or the feeling of incomplete emptying)
  • A change in the appearance or consistency of bowel movements such as thin bowel stools
  • Abdominal pain or swelling
  • Pain or a lump in the anus or rectum
  • Unexplained tiredness as a result of loss of blood (anaemia)
  • Blood in urine (dark, rusty or brown colour) or passing urine frequently or during the night.

Screening and diagnosis for bowel cancer

The average age at diagnosis is 69 years old. People aged 50-74 are sent a bowel screening test every two years as part of the National Bowel Cancer screen program.

If you have any concerns about your risk, or are experiencing any of the symptoms listed previously, see your doctor. Your GP will perform a physical examination and may order tests or refer you for a colonoscopy.

People from families with a history of bowel cancer need extra testing to find bowel cancers early which might include regular colonoscopies.

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