Bowel Cancer
Bowel cancer is common in New Zealand
Bowel cancer, also called colorectal cancer, starts in the colon or the rectum. These cancers can also be called colon cancer or rectal cancer, depending on where they start. Colon cancer and rectal cancer are often grouped together because they have many features in common.
Bowel cancer has received more publicity in recent times because the New Zealand bowel cancer screening programme . In addition, for reasons that are unclear, there is a an increasing incidence of bowel cancer in younger people and therefore it can no longer be assumed to be an ‘old person’ disease.
Bowel cancer occurs in approximately 2,800 New Zealanders each year and is the second leading cause of cancer death, mainly because it commonly becomes symptomatic only when relatively advanced. Therefore, a screening colonoscopy at a younger age (45 is the age recommended in the US) is the best protection against developing bowel cancer, as these cancers come from polyps, and polyps are easily removed at colonoscopy.
In a public healthcare system - such as New Zealand’s - it is too expensive and resource intensive for colonoscopies to be offered to all people, and is instead offered to only those individuals who have a predicted risk of colorectal cancer at least twice that of the average. For those who can afford it, or who have healthcare insurance that covers it, a colonoscopy is the best way to prevent the development of cancer because polyps are removed before they can grow into cancer.
What are the symptoms?
Symptoms that might indicate bowel cancer include:
How is it detected?
The test used is a colonoscopy. In older people who might not be able to tolerate the bowel cleansing process or the colonoscopy itself, there is an alternative called CT colonography which uses a CT scanner.
How do I reduce my risk?
Unfortunately, bowel cancer can affect anyone, even without obvious risk factors. While the first four lifestyle factors listed below might influence your risk over a lifetime, the most important actions you can take are:
Be aware of symptoms that might indicate large polyps and seek prompt investigation; and
Engage in bowel cancer screening, either through the national screening programme or through self-funded colonoscopy.
Additionally, these lifestyle factors may help lower risk:
Eat a diet rich in vegetables and whole grains.
Limit cured meats like bacon and salami.
Avoid smoking and excessive alcohol consumption.
Exercise regularly and maintain a healthy weight.
Who is at increased risk?
A family history of bowel cancer might indicate that there is a faulty gene, or causative bacteria, passed down from generation to generation that increases the risk of developing cancer.
Bowel cancer is common, so by chance alone many people will have a relative with such a cancer, and most of the time this will have little implication for others in the family. If, however, the relative is first degree (First Degree Relative: brother, sister, mother, father, children), and particularly if they were younger than 55 years old when affected, then a faulty gene is more likely. This may have important implications for all family members, more so if multiple individuals on the same side of the family are also affected.
Other people who may have an increased risk of bowel cancer include those with longstanding colitis, such as ulcerative colitis or Crohn's disease, and those who have had certain types of polyps found in prior colonoscopies.
Currently, New Zealanders are eligible for a screening colonoscopy on the basis of family history in most public hospitals if:
One FDR was affected when younger than 55 years of age
More than one FDR, or a FDR and multiple second degree relatives (Second Degree Relative: aunt, uncle, grandparents), on the same side of the family are affected at any age.
If you are concerned about your risk of bowel cancer due to it occurring in family members then you could ask your GP for advice. If your family history is complicated then your GP may refer you to the NZ Familial GI Cancer Registry or you may contact them yourself.
Dr Cameron is also available for consultation to talk through your concerns and make a plan for your care.