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Bowel cancer

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What is bowel cancer?

Bowel cancer is the second most common cancer in both men and women in Australia and is more common in people over the age of 50.1

Bowel cancer, also known as colorectal cancer, develops from the inner lining of the bowel and is preceded by growths called polyps, which may become invasive cancer if undetected.

In 2012, 14,957 new cases of bowel cancer were diagnosed in Australia. The risk of being diagnosed by age 85 is 1 in 11 for men and 1 in 15 for women.

Bowel cancer symptoms

Symptoms of colorectal cancer include:

  • change in bowel habit with diarrhoea, constipation or the feeling of incomplete emptying
  • thin bowel movements
  • blood in the stools
  • abdominal bloating or cramping
  • weight loss
  • fatigue
  • unexplained anaemia.


If you have any of these symptoms you may not have bowel cancer but it is important to see your GP.

Causes of bowel cancer

There are no known causes of bowel cancer, however there are some factors that increase the risk, including:

  • inherited genetic risk and family history
  • inflammatory bowel disease
  • high red meat consumption, especially processed meats
  • being overweight or obese
  • high alcohol consumption
  • smoking.

Screening for bowel cancer

Screening, using a non-invasive test for blood in the faeces that can be done at home, is recommended for all Australians aged 50 to 74.

The National Bowel Cancer Screening Program currently provides the test free for people aged 50, 55, 60, 64, 65, 70, 72 and 74. More aged groups will be added in coming years and by 2020, the test will be available free (once every two years) to all Australians aged 50 to 74.

Diagnosis for bowel cancer

A number of tests are used to diagnose bowel cancer.


The best test for bowel cancer is a colonoscopy, which examines the length of the large bowel. Air is pumped into the colon through a flexible tube that is inserted into the anus. A camera on the end of the tube allows your doctor to look for abnormal tissue that is removed for further examination.

Flexible sigmoidoscopy is used to examine the rectum and left side of the lower colon. Any unusual tissue can be removed for further examination.

CT or MRI scan

CT scans produce three-dimensional pictures of several organs at the same time and can be used to examine the bowel. An MRI scan produces detailed cross-sectional pictures of the body and can show the extent of any tumours.

Barium enema

Using a white contrasting liquid (Barium), a barium enema is a type of x-ray that will show any swellings or lumps.

PET scan

In a positron emission tomography (PET) scan, a small amount of radioactive glucose is injected into the body. When scanned, cancer cells will appear brighter.


This is a test using soundwaves that echo when something dense is encountered such as a tumour. An abdominal ultrasound is used to see if the cancer has spread to the liver whereas an endorectal ultrasound (ERUS) is done if other tests have shown cancer in the rectum or anus.


Treatment for bowel cancer


Tests that help show if you have cancer may also indicate how far the cancer has spread, which is known as staging.

This helps your doctors decide on the best treatment options for you.

A CT scan can be used to detect spread to the liver or lungs. A blood test to check if CEA (carcinoembryonic antigen) is elevated can be used to monitor the progress of the disease.

Types of treatment

The most common treatment for bowel cancer is surgery alone to remove the bowel and surrounding lymph nodes. You may also have chemotherapy, especially if the cancer is more widespread.  More recently targeted therapies are being trialled in addition to chemotherapy.

Treatment team

Your treatment team may be made up of a number of specialist staff such as:

  • colorectal surgeon who diagnoses and operates on bowel cancer
  • gastroenterologist who specialises in the digestive system
  • medical and radiation oncologists who prescribe and coordinate the course of chemotherapy and radiotherapy
  • cancer nurses
  • other allied health professionals, such as a dietitian, social worker and occupational therapist.

Prognosis for bowel cancer

An individual's prognosis depends on the type and stage of cancer, as well as their age and general health at the time of diagnosis. Across all cases, the five year survival rate for Australians diagnosed with bowel cancer is 66%.

In 2013, there were 4162 deaths caused by bowel cancer in Australia. This represents the second highest number of cancer deaths after lung cancer.

Preventing bowel cancer  

The risk of bowel cancer can be reduced by not smoking, a healthy diet with plenty of fresh fruit and vegetables, and maintaining a healthy body weight.


Understanding Bowel Cancer, Cancer Council Australia © 2013. Last medical review of this booklet: January 2013.

Australian Institute of Health and Welfare. ACIM (Australian Cancer Incidence and Mortality) Books. Canberra: AIHW.

1) Excluding non-melanoma skin cancer, which is the most commonly diagnosed cancer according to general practice and hospitals data, however there is no reporting of cases to cancer registries.


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This page was last updated on: Friday, October 21, 2016