Bowel cancer is a serious disease but, if diagnosed early, is often curable. Bowel cancer is also called colorectal cancer. Blood or mucus in the faeces (poo) may be a symptom of bowel cancer. Other symptoms may include diarrhoea or constipation, bloating or cramps, and constant fatigue. Regular health checks and screening for bowel cancer every two years from the age of 50 is recommended.
Bowel cancer is also called colorectal cancer. It is diagnosed in about 3,700 Victorians and over 12,500 Australians every year. It mostly affects people 50 years of age and over, but it can happen in younger people. It is a serious disease, but if bowel cancer or its precursors (polyps) are diagnosed early, it is often curable.
How bowel cancer develops
The colon and rectum together are known as the large bowel. Bowel cancer usually affects the large bowel. Cancer of the large bowel is also known as colorectal cancer.
Illustration above adapted from original illustration, courtesy of The Cancer Council Victoria.
The bowel is the long ‘tube’ that absorbs water and nutrients from food and processes waste products into faeces. It includes the small bowel, colon and rectum.
As people get older, little lumps called polyps may grow inside the colon or rectum and can become cancerous. A polyp looks like small spots on the bowel lining or like cherries on stalks. Not all polyps become cancerous. If polyps are removed, the risk of bowel cancer is reduced.
The development of bowel cancer generally takes many years. It usually begins in the lining of the colon or rectum. Often, very small amounts of blood, which may not be able to be seen, are leaked from these cancers long before any symptoms develop. This blood is then passed into the faeces.
If untreated, it spreads deeper into the wall of the bowel. From there, it can spread to lymph nodes in the area. Later, bowel cancer can spread to the liver or lungs.
Risk factors for bowel cancer
The causes of bowel cancer are not clearly understood. However, we know that some risk factors make it more likely that a person will develop bowel cancer. These include:
- getting older – bowel cancer more commonly affects people aged 50 and over
- inheriting one of two uncommon genetic disorders – familial adenomatous polyposis (FAP) or hereditary non-polyposis colorectal cancer (HNPCC)
- a personal or strong family history of bowel cancer
- having ulcerative colitis (inflamed colon lining) for more than eight to 10 years
- there is also reasonable evidence that having a diet high in red and processed meat, drinking too much alcohol (more than 12.5 units a week) and smoking may increase your risk of developing bowel cancer. Being overweight or obese (particularly for men) may increase your risk of bowel cancer.
Screening for bowel cancer
Ninety per cent of bowel cancer is curable if it is found early and before it has had a chance to spread.
Screening checks for health problems before they cause symptoms. Bowel cancer screening is looking for early changes in the bowel lining, or signs of a bowel cancer, in healthy people who do not have symptoms.
Screening can find polyps so they can be removed before they turn into cancer. It is one of the most effective ways to prevent bowel cancer developing.
The screening test that is used is called the faecal occult blood test (FOBT). This involves taking tiny samples from two bowel motions (poo) using a test kit. The samples are then posted to a laboratory for testing.
Everyone 50 and over should talk with their doctor about the screening tests that might be best for them, so that any signs of bowel cancer can be picked up early. The Cancer Council recommends doing a screening test every two years to protect yourself against bowel cancer. You can find out more about FOBTs and where to get one at the Cancer Council website.
Symptoms of bowel cancer
In the early stages, bowel cancer often has no symptoms. This means that a person could have polyps or bowel cancer and not know it.
The most common symptoms of bowel cancer are:
- blood or mucus in the faeces
- an unexpected change in bowel habit (for example, diarrhoea or constipation for no obvious reason)
- general discomfort in the abdomen (feelings of bloating, fullness, pain, cramps)
- constant tiredness
- weakness and paleness.
Types of bowel cancer
More than 95 per cent of colorectal cancers are adenocarcinomas. This means they started in the gland cells in the lining of the bowel. Other rare types include squamous cell cancers (in the skin like cells of the bowel lining), carcinoid tumours, sarcomas and lymphomas.
Squamous cells are the skin-like cells that make up the bowel lining along with the gland cells.
Diagnosis of bowel cancer
Several tests can be used to diagnose bowel cancer including:
- rectal examination
- colonoscopy and sigmoidoscopy
- barium enema
- x-ray, ultrasound, rectal ultrasound, CT scan or MRI scan
- blood tests, including a carcinoembryonic antigen (CEA) test – CEA is produced in high quantities by some cancer cells, especially in bowel cancer.
Bowel cancer stages
Knowing if and how far the cancer has spread is called ‘staging’ the disease. Staging helps your doctors to work out the best treatment for you.
In Australia, the staging system for bowel cancer is the Australian Clinico-Pathological Staging (ACPS) System, being:
- Stage A – the cancer is confined to the bowel wall.
- Stage B – the cancer has spread to the outer surface of the bowel wall.
- Stage C – cancer is found in lymph nodes near the bowel.
- Stage D – cancer is found at distant sites, for example, in the liver or lungs.
Another staging system being used more often is called the TNM system. It records how far the tumour (T) has spread through the bowel wall, if lymph nodes (N) are affected by the cancer and whether the cancer has spread (metastasised) to other parts of the body (M).
Ask your doctor to explain the stage of your cancer in a way you can understand. This will help you to choose the best treatment for your situation.
Treatment for bowel cancer
Surgery is the main treatment for bowel cancer. The surgeon removes the section of the bowel affected by cancer and then joins the two ends. A stoma (an opening of the bowel onto the abdomen) is sometimes made during the surgery. Your bowel motions will come through the stoma into a bag.
Stomas are usually temporary, while the bowel heals, but some people will need them permanently. Understandably, many people find this difficult to deal with. Before your surgery, you will be given a lot of education and support about having a stoma. Chemotherapy or radiotherapy is nearly always used in addition to surgery. Your doctor will discuss your treatment in detail with you.
It’s common for people with cancer to seek out complementary or alternative treatments. When used alongside your conventional cancer treatment, some of these therapies can make you feel better and improve quality of life. Others may not be so helpful and, in some cases, may be harmful.
It is important to tell all your healthcare professionals about any complementary medicines you are taking, and never stop taking your conventional treatment without consulting your doctor first. The Cancer Council Victoria booklet called Understanding complementary therapies can be a useful resource.
All treatments have side effects. These will vary depending on the type of treatment you are having. Many side effects are temporary, but some may be permanent. Your doctor will explain all the possible side effects before your treatment begins.
Living with a stoma
Most people find it takes time to come to terms with having a stoma. It is a big change in your life. People often worry about how they will care for their stoma. A stomal nurse will explain how to care for your stoma and tell you about support services.
You may also be very concerned about the effect it may have on your personal relationships, sexuality and lifestyle. You may find it difficult or embarrassing to talk about cancer and sexuality. However, most doctors and nurses are very understanding, and even if they're unable to help, they can refer you to a doctor or therapist who specialises in sexual problems.
If you have a partner, it also helps to be as open as possible with them about how you are feeling. The Cancer Council Victoria booklet called Sexuality, intimacy and cancer may also be helpful to read.
Research into bowel cancer
Early detection and better treatment have improved survival for people with bowel cancer. The research is ongoing. Clinical trials can test the effectiveness of promising new treatments or new ways of combining cancer treatments. Always discuss treatment options with your doctor. The Cancer Research UK website has information about research into bowel cancer.
Reducing your risk of bowel cancer
Researchers believe that eating a healthy diet may help prevent as many as one third of all cancers, including bowel cancer. Although there is no one diet that can prevent bowel cancer, changing your diet could help reduce your risk of cancer in general. It will also improve your overall health.
You can help to reduce your risk of bowel cancer by:
- regular screening
- eating a healthy diet, including plenty of vegetables and fruit and only small amounts of animal fat
- eating moderate amounts of lean red meat as part of a mixed diet including carbohydrates (breads and cereals), vegetables and fruit, and dairy products
- eating limited amounts of processed meats
- maintaining a healthy body weight
- exercising regularly
- not smoking or drinking too much alcohol.
Caring for someone with bowel cancer
Caring for someone with cancer can be a difficult and emotional time. If you or someone you know is caring for someone with bowel cancer, there is support available. The Cancer Council Victoria booklet called Caring for someone with cancer may also be helpful to read.
When a cure isn’t possible
If the bowel cancer has spread to other parts of the body, it is not always possible to cure. However, in a lot of people, it is still likely that the cancer can be kept under control for quite a long time. This depends on:
- where and how far the cancer has spread
- what treatment you have had in the past
- the type of bowel cancer you have.
Where to get help
- Your doctor
- Colorectal specialist
- Multilingual Cancer Information Line, Victoria Tel. 13 14 50
- Cancer Council Helpline Tel. 13 11 20
Things to remember
- If you are 50 years of age or over, talk to your doctor about bowel cancer and screening.
- Most bowel cancers diagnosed at an early stage are curable.
- If you are at risk of bowel cancer, discuss with your doctor whether you need to have regular tests.
- You can reduce your risk of bowel cancer by eating a healthy diet, maintaining a healthy body weight, exercising regularly and not smoking.
You might also be interested in:
- Cancer and food.
- Cancer and heredity.
- Cancer screening.
- Fibre in food.
- Palliative care for adults with a life-threatening condition.
- Rectal cancer.
Want to know more?
Go to More information for support groups, related links and references.
This page has been produced in consultation with and approved by:
(Logo links to further information)
The Cancer Council Victoria
Last reviewed: May 2014
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