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What is bowel cancer?

Bowel cancer is the second most common cancer in both men and women in Australia (excluding non-melanoma skin cancer) and is more common in people over the age of 50.

Bowel cancer, also known as colorectal cancer, develops from the inner lining of the bowel and is usually preceded by growths called polyps, which may become invasive cancer if undetected. Depending on where the cancer begins, bowel cancer may be called colon or rectal cancer. 

In 2016, 15,352 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 16 for women.

In 2018, there were 5336 deaths caused by bowel cancer in Australia. This represents the second highest number of cancer deaths in Australia.

The five year survival rate for bowel cancer is 70.1%.

Learn more about how Cancer Council researchers are tackling bowel cancer on a national scale.

Bowel cancer symptoms

Symptoms of bowel cancer include:

  • change in bowel habit with diarrhoea, constipation or the feeling of incomplete emptying

  • thin bowel movements

  • blood in the stools

  • abdominal pain, bloating or cramping

  • anal or rectal pain

  • a lump in the anus or rectum

  • weight loss

  • blood in the urine.

Causes of bowel cancer

Some factors that increase your risk of bowel cancer include:

  • inherited genetic risk and family history

  • inflammatory bowel disease

  • polyps

  • high red meat consumption, especially processed meats

  • being overweight or obese

  • high alcohol consumption

  • smoking.

Diagnosis of bowel cancer

A number of tests are used to diagnose bowel cancer. Initially your doctor will give you a physical examination to feel if you have any abdominal swelling. 

Blood tests

You may have a blood test to see if there are any signs that you are losing blood in your stools. It can also check your red blood cell count. 


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.


An MRI scan produces detailed cross-sectional pictures of the body and can show the extent of any tumours.

CT scan

CT scans produce three-dimensional pictures of several organs at the same time and can be used to examine the bowel.

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.

After a diagnosis of bowel cancer  

After finding out you have bowel cancer, you may feel shocked, upset, anxious or confused. These are normal responses. A diagnosis of bowel cancer affects each person differently. For most it will be a difficult time, however some people manage to continue with their normal daily activities.  

Find out more information after a diagnosis of bowel cancer:

Treatment for bowel cancer

Treatment for early bowel cancer


The main treatment for early bowel cancer is surgery. The most common surgery for cancer that begins in the colon is a colectomy. The type of colectomy performed will depend on whether all or part of the colon needs to be removed.

Radiation therapy (radiotherapy)

Radiation therapy (radiotherapy) is often used before surgery for locally advanced rectal cancer and may be used in combination with chemotherapy to reduce the number and size of cancer cells.

Adjuvant treatment

Chemotherapy may be recommended after surgery for rectal or colon cancer. This aims to reduce the risk of the cancer returning.

Palliative care

In some cases of bowel cancer, your medical team may talk to you about palliative care. Palliative care aims to improve your quality of life by alleviating symptoms of cancer, without aiming to cure it.

As well as slowing the spread of bowel cancer, palliative treatment can relieve pain and help manage other symptoms. Treatment may include radiotherapy, chemotherapy or other drug therapies.

Treatment for advanced bowel cancer

Systemic treatment

Systemic treatment for advanced bowel cancer uses drugs that move through the bloodstream to reach cancer cells throughout the body. Systemic treatment can include chemotherapy and targeted therapies.


You may be offered surgery to remove small secondary cancers if the cancer has spread to other areas of the body.

Treatment Team

Depending on your treatment, your treatment team may consist of a number of different health professionals, such as:
  • GP (General Practitioner)- looks after your general health and works with your specialists to coordinate treatment.
  • Colorectal surgeon- diagnoses bowel cancer and performs bowel surgery.
  • Gastroenterologist- specialises in diseases of the digestive system.
  • Medical oncologist- prescribes and coordinates the course of chemotherapy.
  • Radiation oncologist- prescribes and coordinates radiation therapy treatment.
  • Cancer nurses- assist with treatment and provide information and support throughout your treatment.
  • Other allied health professionals- such as social workers, pharmacists and counsellors.

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. Known as the faecal occult blood test (FOBT), the test is only for low-risk people with no symptoms of bowel cancer. The FOBT is not for people with a family history of bowel cancer. In this case, you may need screening colonoscopies.

As of 2020 the National Bowel Cancer Screening Program, using FOBT, will be offered free every two years to all Australians aged 50 to 74. 

For further information call 1800 118 868 or visit

Preventing bowel cancer

The risk of bowel cancer can be reduced by not smoking, a healthy diet with plenty of fresh fruit and vegetables, limiting consumption of red meat, avoiding processed meats, and maintaining a healthy body weight.

Prognosis for bowel cancer

Prognosis refers to the expected outcome of a disease. It is not possible for any doctor to predict the exact course of the disease. 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. This information will also help your doctor to advise on the best treatment options. 

Generally, the earlier bowel cancer is diagnosed, the better the outcomes. 


Understanding Bowel Cancer, Cancer Council Australia © 2019. Last medical review of source booklet: January 2019. 

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