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Colorectal (Bowel) Cancer


In Australia bowel cancer, also known as colorectal cancer, affects roughly one in twenty people at some point during their lives. Most commonly bowel cancer develops in the lower section of the bowel (the rectum and the sigmoid colon), followed by the first section of the bowel, which comprises two sections -  the caecum and the ascending colon.


It is not known exactly what causes bowel cancer, however there are a number of factors that are now recognised as playing a role in the likelihood of an individual developing bowel cancer. These risk factors are...

  • Age – bowel cancer is more prevalent in older people (50+) and rare in younger people.
  • Gender – men are slightly more likely to develop the condition than women.
  • Family history – this is important especially where a close family member has developed the condition at a young age or a number of close relatives have been affected by the condition.
  • Diet – a diet high in fruit and vegetables and related fibre and low in animal fats and meat protects against the development of bowel cancer and one low in fruit and vegetables and high in animal fats is correlated with an increased risk of developing the condition.
  • Lifestyle – people who do not have much physical activity in their day-to-day life and those that are largely sedentary and / or overweight or obese are at a higher risk of developing the condition.


Bowel cancer may be present without any outward symptoms being apparent, however the following are possible symptoms of the condition, which should be investigated...

  • Rectal bleeding.
  • Any change in bowel habit.
  • Pain or any swelling in the abdominal area.
  • Constant tiredness or fatigue (which may indicate anaemia caused by bleeding inside the bowel).
  • Unexplained weight loss.

Tests / Diagnosis

Everyone over the age of 50 - even where there is no family history or other major risk factors present - is advised to take a regular Faecal Occult Blood Test (FOBT) which allows a sample of the stool to be checked for the presence of blood otherwise invisible to the naked eye. Where blood is detected, a colonoscopy is strongly recommended.

Bowel cancer first develops as a polyp and early removal of polyps (often during a colonoscopy) is the best way of reducing the risk of the development of the invasive form of bowel cancer.

Most incidences of bowel cancer require surgical treatment.