Your risk of bowel cancer increases 2 to 4 times if:
- You have one or more close relatives (mother, father, sister, brother, child) who have had bowel cancer polyps
- You have already had bowel cancer or polyps
- You have had extensive ulcerative colitis
Among those who develop bowel cancer, four out of five have no known risk factors. Screening aims to identify individuals in the community who have plyps or early cancer but no risk factors and no symptoms.
All Australians at the age of 40 years should talk to their doctor about the screening options to prevent bowel cancer.
If detected early, bowel cancer may be curable. Most bowel cancers cause no symptoms until they are advanced. Bleeding from the bowel (always look in the toilet bowl) needs investigation. See your doctor without delay.
Persistent change in bowel habit – diarrhoea, constipation or abdominal pain.
These symptoms often have other causes, but should always be investigated.
Tests available for screening
Faecal Occult Blood Test (FOBT)
Most cancers and large polyps bleed. Often there is only a small amount of blood, which is not noticeable, but can be detected with a chemical test applied to a sample of the bowel motion.
A positive test must be followed by a colonoscopy.
As not all cancers or polyps bleed a negative test does not necessarily exclude cancer or polyps, so the test should be done each year. There is still debate about the age tests should begin, with various authorities recommending somewhere between 40-55 years of age.
The Gut Foundation recommends annual faecal occult blood testing should begin at age 40.
Sigmoidoscopy has important advantages over FOBT. The bowel is seen directly so this test is highly specific for polyps or early cancer in the part of the bowel examined. However, sigmoidoscopy has limited use because, at best, it only examines half the bowel.
Combined FOBT and flexible sigmoidoscopy
Flexible sigmoidoscopy will only detect polyps within its range and may miss polyps and early cancer beyond the reach of the instrument. To increase its success, it is suggested flexible sigmoidoscopy should be combined with annual FOBT to detect polyps further inside the bowel.
A lighted flexible tube examines the whole colon. The direct views allow all polyps to be detected and removed. Colonoscopy is the recommended test for individuals at higher risk who require surveillance. I requires a day hospital admission and sedation to avoid discomfort and is an alternative screening option to FOBT/flexible sigmoidoscopy.
In most developed countries, colonoscopy is regarded as the most cost effective screening examination.
Options for screening those at average risk after the age of 40
- Annual FOBT
- Flexible sigmoidoscopy every 5 years
- Annual FOBT plus flexible sigmoidoscopy
- Colonoscopy every 5-10 years
Which is the best test? The one that gets done!
Bowel cancer is the most common internal cancer in Australia (after prostate cancer in men and breast cancer in women) and is the leading cause of cancer death in non-smokers. It is the only potentially preventable cancer in men and one of two in women, the other being cervical.
1 in 20 Australians will develop bowel cancer. The risk begins to rise after the age of 40 and continues to increase with age.
One Australian dies every five hours from a motor car accident, one woman dies every four hours from breast cancer and one person dies every two hours from bowel cancer yet most bowel cancers can be prevented.
Polyps are growths which can occur on the lining of the bowel. Most bowel polyps are not cancerous but nearly all bowel cancers start as polyps. While they may bleed, and occasionally cause diarrhoea or pain, most polyps cause no symptoms. Because any bowel polyp can develop into cancer, all bowel polyps should be removed.
Preventing bowel cancer depends on finding and removing all bowel polyps during colonoscopy.
A diet high in saturated fat, processed meat and beer may be related to bowel cancer and excess weight increases the risk.
Eating fibre-rich foods and plenty of fruits and vegetables may give come protection. The typical Australian diet is high in fat and most people do not eat enough dietary fibre.
To minimise the risk of bowel cancer you should:
Eat less fat, especially saturated fat
Eat more high-fibre foods such as wholegrain breads and cereals
Eat plenty of fruits, vegetables and legumes (see The Gut foundation’s booklets, Dietary Fibre & Health or The Good Gut Cookbook)
- If you drink alcohol, do so in moderation
- Stop smoking
- Exercise regularly and maintain a normal weight
- Ensure good intake of calcium
- Early diagnosis and removal of polyps is important
- Check if you are in a high risk group
- Do not ignore rectal bleeding
The Cancer Council Australia
The Cancer Council Australia is the country's peal cancer control body, funding cancer research and providing education as well as support for people affected by cancer. Its members are the eight state and territory cancer councils.
Cancer Helphline: 13 11 20
Telephone: 13 11 20
The Cancer Council NSW
Call 13 11 20 between 9am and 8pm for information and advice concerning Bowel Cancer.
PO Box 572
KINGS CROSS NSW 2011
Telephone: (02) 9334 1900
Facsimile: (02) 9358 1452
The Australian Cancer Network
Telephone: (02) 9036 3120
The Gut Foundation Research Institute