About bowel cancer

The bowel | Reduce your risk | Screening | Diagnosis | Treatment | Coping with Cancer | Support Services | More information and resources | References

The bowel

The bowel is part of our digestive system. The digestive system starts at the mouth and ends at the anus. It has two main functions:

  • It helps the body to break down and absorb the food we eat.
  • It deals with waste products from the food we eat. This solid waste matter is called poo, stools or faeces.

The bowel is made up of two sections, the small and the large bowel.

  • The small bowel is where broken down food is absorbed into our body.
  • The large bowel is where water and salts are absorbed. The large bowel has two parts: the colon, which is about one and a half metres long, and the rectum, which is about 15 centimetres long.


Image courtsey of Cancer Council Victoria

[return to top]

Bowel cancer

Bowel cancer is the growth of abnormal cells in the large bowel (the colon or rectum).

Bowel cancer usually develops from polyps - these are growths on the inner lining of the bowel.  Many people have polyps, most of which do not become cancer (they are benign). However as polyps can be an early warning sign for bowel cancer they should be removed when possible.

If left untreated, some polyps may become larger and the cells within may change and become malignant (cancer). When this happens the cancer often ulcerates (becomes an open sore) 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.

Bowel cancer is preventable and the best way to protect yourself is to participate in screening as this helps to find polyps and cancer early.

How common is it?

Bowel cancer is one of the top cancers affecting men and women in Western Australia. In 2014, 1229 people were diagnosed with bowel cancer (739 men, 560 women).1

The chances of getting bowel cancer by the time you are aged 85 (lifetime risk) is 1 in 13.2  Men are slightly more at risk than women (lifetime risk 1 in 11 for men, and 1 in 16 for women). In 2014, 440 Western Australians died from bowel cancer (241 men, 199 women).1

Learn more about bowel cancer statistics.

[return to top]

Risk factors

You can get bowel cancer at any age, but you are more likely to get it if you are over the age of 50.

There are a number of factors that are known to increase the risk of developing bowel cancer - some of these are beyond your control, while others are not.

Lifestyle factors are things you can change. Your risk of bowel cancer is increased if you:3,4,

Other risk facts that are out of your control and can increase your risk include:3

  • previous history of bowel cancer or polyps
  • a strong family history of bowel cancer (15% to 20% of people with bowel cancer have a history of the disease within their family)
  • chronic inflammatory bowel disease (ulcerative colitis and Crohn's disease)
  • a rare inherited genetic disorder, such as Familial Adenomatous Polyposis (FAP) and Lynch syndrome (formerly known Hereditary Non-Polyposis Colorectal Cancer (HNPCC)). Together they account for less than 5% of all bowel cancers.
  • Type 2 diabetes and increased insulin levels

If you have any of these risk factors, we strongly advise you to contact your doctor.

There are two risk calculators that have been developed in Australia. One looks at overall risk, including lifestyle factors while the other looks at family history.

[return to top]


Symptoms of bowel cancer may include one or more of the following:4

  • Bleeding from your back passage (anus) or any sign of blood after a poo/bowel motion (this could be red to black)
  • A change in bowel habit for example, straining to go to the toilet (constipation) and/or looser bowel motions (diarrhoea)
  • Abdominal pain and bloating
  • Loss of weight for no obvious reason
  • Loss of appetite
  • Symptoms of anaemia including unexplained tiredness, weakness or breathlessness

If any of these symptoms are unusual for you, and they persist, it's important to see your doctor.

It is important to know these symptoms, but it is equally important to know bowel cancer often develops without symptoms. What's more, having these symptoms does not mean you have bowel cancer, as they may be caused by other conditions. For example, rectal bleeding may be the result of haemorrhoids or piles.1 However, if you do have any of these symptoms you should see your doctor as soon as possible.

Many people experiencing symptoms of bowel cancer delay 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 as soon as possible. Remember the earlier a diagnosis is made, the better chances of successful treatment. As cancer progresses, the chances of survival decrease.

[return to top]

Reduce your risk

Bowel cancer is one of the most preventable cancers.

There are a number of things you can do to help reduce your chances (risk) of developing bowel cancer including:4

  • Take part in the National Bowel Cancer Screening Program 
  • Quit smoking
  • Achieve and maintain a healthy body weight
  • Get at least 30 to 60 minutes or more of moderate intensity physical activity on most days of the week
  • Eat well - enjoy a wide variety of nutritious foods from the five groups every day
    • Plenty of vegetables, including different types and colours, and legumes/beans
    • Fruit
    • Avoid processed meats
    • Limit your intake of red meat to 3 or 4 palm sized serves (65-100g) a week.
    • Eat foods which are high in fibre
  • Avoid alcohol. If you choose to drink, limit your alcohol intake

[return to top]


Screening for cancer means finding early cancer before symptoms develop. Screening does not diagnose cancer, it identifies people who need more tests to find out if cancer is present.2

As bowel cancer is a common cancer, screening can significantly reduce the impact it has on the Australian population.9 Early detection of bowel cancer significantly improves the chances of successful treatment.

How do I screen for bowel cancer?

The immunochemical faecal occult blood test (iFOBT) is currently the best screening test available for bowel cancer and could reduce bowel cancer deaths by up to 25%.2

An iFOBT is a simple, non-invasive test that looks for hidden blood in a poo/bowel motion. It works because polyps and bowel cancer are known to bleed. This test is unable to distinguish between blood that has been shed by cancers and blood caused by other problems, such as haemorrhoids. As the iFOBT does not diagnose bowel cancer, if blood is found more tests are required.

An iFOBT can be done at home and involves taking samples from two or three poos/bowel movements using a test kit.

[return to top]

National Bowel Cancer Screening Program

The National Bowel Cancer Screening Program sends eligible men and women a free, easy to use screening kit that can be completed at home. Invitees' names are drawn from either the Medicare or Department of Veterans' Affairs enrolment records. The Program uses the immunochemical faecal occult blood test (iFOBT) to screen for bowel cancer.

The table below shows at what age people will be invited as the Program moves towards 2 yearly screening.

Year Eligible ages
2018  50, 54, 58, 60, 62, 64, 66, 68, 70, 72, 74
2019 onwards  50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74

If you are eligible to participate in the Program, you will be contacted by mail and sent the iFOBT kit, which includes a description of how to complete the test. If you need help, you can use the Invitation Pack - Home Test Instructions found here.

If you participate in the Program your results will be sent to you and your nominated doctor in the mail. Most people that are tested (92%) are likely to have a negative result.5

The small number of people who have a positive test will be sent for more tests, which may include referral to undergo a colonoscopy. Only a small number of people (4%) who have this follow-up colonoscopy will have bowel cancer but many will have a pre-cancerous growth called an adenoma.4, 5


Why not check if you will to receive a bowel cancer screening kit this year.

What to do if you are ineligible for the National Bowel Cancer Screening Program

Some GPs are able to provide patients with a screening FOBT or refer patients to a pathology laboratory to complete an iFOBT (this usually involves providing a bowel motion sample in a specimen collection jar for the pathology laboratory to test it).

[return to top]


If you have any signs or symptoms of bowel cancer or have had a positive iFOBT, you need to visit your doctor without delay and you may be referred for further tests such as a colonoscopy. Having signs and symptoms or a positive FOBT does not mean you have bowel cancer, but it means that something needs checking.

This can be a worrying time, especially if you need to have several tests. If the tests show you have or may have cancer, your doctor will refer you to a specialist, who will talk to you about treatment options.

What is a colonoscopy?

bowel-colonoscopyA colonoscopy allows the doctor to look at the inside of your bowel using a colonoscope. A colonoscope is a long, thin, flexible tube with a built-in light and camera that is connected to a video monitor.4 The colonoscope is passed into the large bowel through the anus, and the entire length of the bowel is inspected.

Any polyps or tumours (bowel cancer) that are found can be removed during the colonoscopy procedure, provided they are not too large.4

A colonoscopy is usually done under sedation.

[return to top]

Bowel preparation

Before undergoing a colonoscopy, you will be required to prepare your bowel. To do this, you will need to drink a large amount of bowel preparation liquid - this causes watery diarrhoea/poo, which cleans and empties the bowel.

You will be given special instructions by your doctor that may include following a certain diet and fasting. It is important to follow these instructions carefully so that your bowel will be clean enough for the doctor to see everything clearly.

In some cases, you may be given an enema. This is when fluid is put into your rectum. This will give you watery diarrhoea that will empty your bowel.

What to ask your doctor or specialist?

A cancer diagnosis can be a very confusing time. There are many different cancers so it is important to find out information that is relevant to you.

There are several things you can do to help prepare for your appointment and to improve your understanding.

  • It can be helpful to write a list of questions to ask your doctor or specialist. You may need to ask for a longer appointment.
  • Take some paper and a pen so that you can write down notes and instructions
  • Take a relative or friend with you for support - it can be helpful to have an extra person to hear what is being said and write down any notes
  • It may be helpful to record your visit - make sure you ask your doctor if it's okay. Remember, many smart phones and mp3 players can make audio recordings

[return to top]


If you have been diagnosed with bowel cancer, you should expect to be cared for by a multidisciplinary team (MDT). This is a group of doctors and other health professionals who are experts in a specific cancer who work together to plan the best treatment for you. Everyone's treatment is different and depends on the type of cancer and how far the cancer has spread.

Stages of cancer

Staging is used to determine if and how much a cancer has spread and is used to determine treatment options and survival outcomes (prognosis) for cancer patients post diagnosis.

In Australia, one of the most common staging systems for bowel cancer is Australian Clinico-Pathological Staging. It describes bowel cancer stages as:

  • Stage 1: The cancer is confined within the bowel wall
  • Stage 2: The cancer has spread to the outer surface of the bowel wall and not beyond
  • Stage 3: The cancer has spread to lymph nodes outside the bowel wall and not beyond
  • Stage 4: The cancer has spread to other parts of the body


Prognosis means the expected outcome of a disease. In most cases, the earlier bowel cancer is diagnosed and treated, the better the outcome.2

You may wish to discuss your prognosis and treatment options with your doctor, but it's not possible for any doctor to predict the exact course of your cancer. Test results, the type of cancer you have, the rate and depth of tumour growth, how well you respond to treatment, and other factors such as age, fitness and medical history are all important in assessing your prognosis.

[return to top]

Types of treatment

The type of treatment for bowel cancer depends on the stage at diagnosis and can be different for everyone. If you or someone you know has been diagnosed with cancer, you may have many questions and concerns and need more information to help you make decisions about your treatment.

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.

Treatment for bowel cancer may be one, or a combination of the following:

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.4 Usually the bowel can be joined together again to restore normal function. If for some reason it cannot be re-joined, an artificial opening (colostomy) for faecal waste is made in the wall of the abdomen. In many cases, a colostomy is short term to allow for healing and once the bowel is healed the colostomy is removed and the bowel joined back together.

Bowel surgery is a major operation with an average hospital stay of five to 10 days followed by four to six weeks of recovery.

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

Chemotherapy uses anti-cancer drugs to help destroy cancer cells that may have spread to other areas of your body but cannot be detected. Chemotherapy after surgery can reduce the chance of the cancer coming back.

Radiation therapy uses x-rays to destroy cancer cells. It can be used before or after surgery for cancer to reduce the tumour size and make surgery easier. It is also used to decrease the chance of cancer coming back.

Complementary therapies can work alongside medical treatments and some have been shown to improve quality of life or reduce pain. There is no evidence that these therapies can cure or prevent cancer.

It is important to know that some complementary therapies have not been tested for side effects, may work against your medical cancer treatment and may be expensive. Let your doctor know about all complementary therapies you are thinking of using.

For more information about complementary therapies visit Memorial Sloan-Kettering Cancer Centre's About Herbs, Botanicals and Other Products.

[return to top]

More information and resources

Visit Cancer Council WA's publications page to view the following resources.

Understanding Bowel Cancer (pdf)
Bowel Cancer Brochure (pdf)
Colonoscopy - After a positive FOBT fact sheet (pdf)

Visit the National Bowel Cancer Screening Program for additional videos, factsheets and pamphlets

[return to top]


  1. Threlfall TJ, Thompson JR. Cancer incidence and mortality in Western Australia, 2014. [Internet] Perth: Department of Health; 2015 [cited 2017 February 15]; Available from: http://www.health.wa.gov.au/wacr/statistics/stats_full.cfm.
  2. Australian Institute of Health and Welfare, Department of Health and Ageing. Cancer in Australia 2017. Canberra: Australian Institute of Health and Welfare, Department of Health and Ageing, 2017.
  3. World Cancer Research Fund/American Institute for Cancer Research. Diet, Nutrition, Physical Activity and Cancer: a Global Perspective [Internet]. ; 2017 [cited 2018 September 12]. Available from: https://www.wcrf.org/dietandcancer/recommendations-about#download_block.
  4. Australian Cancer Network Colorectal Cancer Guidelines Revision Committee. Clinical practice guidelines for the prevention, early detection and management of Colorectal Cancer. Sydney: The Cancer Council Australia and Australian Cancer Network,; 2005 [cited 2013 June 18]. Available from: http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/cp106_0.pdf.
  5. Australian Institute of Health and Welfare, Department of Health and Ageing. National Bowel Cancer Screening Program: Monitoring Report 2018. Canberra: Australian Institute of Health and Welfare, Department of Health and Ageing, 2018.

[return to top]