New Zealand has the world’s highest rate of colon cancer in women and the rate in men is not far behind. In New Zealand there is a high rate of bowel cancer presentation as a surgical emergency with obstruction or perforation of the colon with an associated high rate of advanced stage of disease at diagnosis compared to Australia and the United States where the disease is diagnosed at an earlier stage with a significantly better chance of cure.
Who is at Risk of colon and rectal cancer (CRC)?
Both men and women are at risk and the risk rises with age especially after the age of 50. Younger people may also develop colorectal cancer (bowel cancer) sometimes associated with a genetic mutation inherited from one or both parents or as a new mutation in tumour suppressor gene.
What are the symptoms of colon and rectal cancer?
Unfortunately bowel caner is often a “silent disease” in its early stages, hence the need for a screening programme, and the use of colonoscopy to find and remove the precursor adenomatous or serrated polyps. These may be present for up to 10 years before a cancer develops.
Bleeding from the bowel, a change in bowel habit, new onset iron deficiency or iron deficiency anaemia and abdominal pain are all symptoms of bowel cancer.
How can I reduce my risk?
A healthy weight, regular exercise, non-smoking and a low alcohol intake are all associated with a reduced rate of bowel cancer. Preserved meat and heavy red meat consumption are associated with an increased rate of bowel cancer.
The national bowel cancer screening programme
This programme is currently being rolled out nationally and will offer a test to the population over the age of 60 involving a faecal occult blood test (looking for blood in the stool) every two years. A positive test will lead to a colonoscopy.
What is the role of colonoscopy?
Patients at moderately increased risk : a first degree relative with bowel cancer under the age of 55 or two first degree relatives on the same side of the family at any age should have colonoscopy 5 yearly starting ten years younger than the youngest relative with the disease and this should be performed five yearly. Other combinations of family history or other risk factors need discussion with your doctor. Certain hereditary conditions may need careful assessment by the New Zealand Familial Gastrointestinal Cancer Service (NZFGCS), a National service that looks after high risk families (Lynch Syndrome, FAP, MYH, juvenile polyposis, serrated polyposis etc.) and detailed management plans will be made for patients and their relatives in this situation.
Patients with previous bowel cancer, adenomas, sessile serrated polyps and previous cancers also require regular colonoscopy.