Health conditions

Bowel cancer

  • With more than 1,330 people diagnosed each year, bowel cancer is the most common internal cancer in WA.
  • Bowel cancer causes the second highest number of cancer deaths, after lung cancer.
  • Bowel cancer is one of the most preventable cancers.
  • Although nearly all treatments have side effects, most can be effectively managed.

What is the bowel?

The bowel is made up of the colon and rectum and forms the lower part of the gastrointestinal tract. The colon and rectum form a muscular tube approximately 1.6m long. They deal with all the waste products that remain in the body after food has been digested and absorbed in the small intestine.

What is bowel cancer?

Bowel cancer is the growth of abnormal cells in the bowel. These abnormal cells grow and divide faster than normal cells.

Bowel cancer usually develops from an existing growth on the inner lining of the bowel or rectum. These growths are called polyps. Many people have polyps, the majority of which are benign (not cancer). However as polyps are an early warning sign for bowel cancer, they need to be removed.

If left untreated, some polyps may become larger and the cells within the polyp may change to become malignant (cancer). When this happens the cancer often ulcerates and bleeds, or may cause a blockage of the bowel. Over time, the cancer is likely to spread through the bowel wall to the blood vessels and lymph nodes, and even to distant organs, especially the liver.

Find out more about the risk factors for bowel cancer.

What are the signs and symptoms?

Symptoms of bowel cancer may include one or more of the following:

  • bleeding from your back passage or any sign of blood after a bowel motion
  • a change in bowel habit (for example, straining to go to the toilet and/or looser bowel motions)
  • swelling, pain or an unexplained lump in the tummy
  • loss of weight for no obvious reason
  • loss of appetite
  • symptoms of anaemia – unexplained tiredness, weakness or breathlessness.

It is important to realise that these symptoms do not necessarily mean you have bowel cancer. For example, rectal bleeding may be the result of haemorrhoids (piles). However, if you do have any of these symptoms you should see your doctor promptly.

Remember that with many cancers, earlier diagnosis is associated with a greater chance of successful treatment. As cancer progresses, the chances of surviving the cancer decreases.

Many people experiencing symptoms of bowel cancer put off seeing their doctor because they are embarrassed to discuss their symptoms. Unfortunately, this embarrassment may put your life at risk. It is important to put embarrassment aside and seek advice promptly.

Find out more about the free National Bowel Cancer Screening Program (external site) which involves testing for bowel cancer in people with no obvious symptoms.

How is bowel cancer diagnosed?

The following tests are used to help determine whether a person has bowel cancer:

  • digital rectal exam (DRE)
  • faecal occult blood test (FOBT)
  • colonoscopy
  • virtual colonoscopy
  • barium enema.

Digital rectal exam

A digital rectal exam is an examination of the rectum to check for any lumps or swelling. During the examination a doctor feels inside the rectum with a lubricated, gloved finger. The procedure may be uncomfortable but should not be painful. A digital rectal examination by itself is not used to diagnose cancer in the lower bowel.

Faecal occult blood test

A faecal occult blood test (FOBT) is a simple, non-invasive test that looks for blood in a bowel movement. An FOBT can be done at home and involves taking samples from two or three bowel movements using a test kit. The National Bowel Cancer Screening Program uses an immunochemical FOBT to screen for bowel cancer. If an FOBT finds blood, further tests are needed, the most common being a colonoscopy.

An FOBT involves using the small collection stick supplied with the FOBT kit to take a sample of your bowel movement. The stick is placed in one of the plastic tubes supplied with the kit, sealed and sent to a laboratory for testing.

People that test negative will be informed by return post. People who have a positive test will be referred to undergo a colonoscopy.

A positive FOBT does not necessarily mean that you have bowel cancer. Only about 5 per cent of people who have the follow-up colonoscopy will have a cancer and about 20 per cent will have a precancerous growth called an adenoma.


A colonoscopy is a test that enables your doctor to look at the inside of your bowel. If a polyp or bowel cancer is found, your doctor can remove it immediately during the procedure.

Colonoscopy is usually performed as a day procedure. Colonoscopies can also be used as a surveillance test for people at an increased risk of developing bowel cancer, for example if they have a strong family history of the disease.

Find out more about colonoscopy.

Virtual colonoscopy

A virtual colonoscopy uses a special type of X-ray, called a computerised tomography (CT) scan, to build a three dimensional picture of the bowel. It will show up any growths on the bowel wall. If growths are found, further tests will be needed to determine if the growths are cancer.

Barium enema

This is a special X-ray of the large bowel. Before the X-ray is taken, a white fluid containing barium (a metallic substance) is run into the bowel through the anus. The barium is later run out of the bowel and air is introduced.

Barium shows up under X-ray, so the X-ray pictures will outline the bowel and show any abnormal areas. If any suspicious or abnormal areas are seen, a colonoscopy is usually required.

How is bowel cancer treated?

The type of treatment you have will depend on whether or not the cancer has spread or is at risk of spreading. Although nearly all treatments have side effects, most can be effectively managed.

Ask your doctor to explain what side effects to expect and how best to manage these.

Treatments for bowel cancer include:

  • surgery
  • radiotherapy
  • chemotherapy.

Surgery for bowel cancer

Surgery is the usual treatment for bowel cancer. It involves removing the cancer as well as surrounding tissue to make sure no part of the cancer is left behind.

Usually the bowel can be joined together again to restore normal function. If for some reason it cannot be rejoined, an artificial opening (colostomy) for faecal waste is made in the wall of the abdomen.

A temporary colostomy can usually be reversed in a few weeks. Less than 5 per cent of people need a permanent colostomy.

Bowel surgery is a major operation with an average hospital stay of 5 to 10 days followed by a recovering period of 4 to 6 weeks. For very early bowel cancers there is usually no need for additional radiotherapy or chemotherapy.

For those with larger tumours or whose cancer has spread to the lymph nodes, the best results are often achieved by combining surgery, radiation therapy and chemotherapy.

Find out more about radiation therapy and chemotherapy.

How can bowel cancer be prevented?

Bowel cancer is one of the most preventable cancers. Lifestyle risk factors attributing to bowel cancer include obesity, physical inactivity, drinking alcohol and poor diet.

Find out more about the risk factors for bowel cancer.

There are a number of things you can do to help reduce your chances of developing bowel cancer including:

  • be screened for bowel cancer using an immunochemical faecal occult blood test (FOBT) every 2 years after the age of 50.
  • if eligible take part in the National Bowel Cancer Screening Program (external site).
  • get at least 30 minutes or more of moderate intensity physical activity on most days of the week.
  • achieve and maintain a healthy body weight.
  • eat a well-balanced and varied diet, which is high in fibre and includes 5 serves of vegetables and 2 serves of fruit every day.
  • avoid processed meat and burnt/charred meat and if you eat red meat try and limit your intake to 3 or 4 palm sized serves (65 to 100g) a week.
  • if you drink, limit your alcohol intake.
  • quit smoking.

Where to get help

More information

More information on bowel cancer is available from Cancer Council Western Australia (external site)

This information provided by
Logo: Cancer Council Western Australia

Cancer Council Western Australia

This publication is provided for education and information purposes only. It is not a substitute for professional medical care. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your healthcare professional. Readers should note that over time currency and completeness of the information may change. All users should seek advice from a qualified healthcare professional for a diagnosis and answers to their medical questions.

Bowel cancer screening program