Bowel cancer often causes no symptoms until it becomes relatively advanced. As 1 in 20 Australians will develop bowel cancer, a National Bowel Cancer Screening Program was introduced in 2008.
Australians who are at average risk for bowel cancer and who have no symptoms, are screened with faecal occult blood testing (FOBT) from age 50-75. Ideally this should be done every 1-2 years.
A positive faecal occult blood test indicates the presence of blood in the stool. This does not indicate bowel cancer, but patients with a positive faecal occult blood test should undergo further testing, usually with colonoscopy. Not all polyps are detected by FOBT and some small cancers can occasionally be missed, which reduces its effectiveness as an ideal screening method.
People who have symptoms such as bleeding or a change in bowel habit, or who have a significant family history of colorectal cancer will usually be investigated with colonoscopy.