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Colon Cancer NZ: Symptoms, Risk & Screening

Bowel cancer is the second highest cause of cancer deaths in New Zealand. Colon cancer is common type of bowel cancer in New Zealand. Colon cancer may not be easily identified in the early stages, so being aware and finding it early saves lives. This ZOOM Pharmacy guide explains what colon cancer is, who is at risk, symptoms, how screening works, and how to lower your risk in New Zealand.

Colon cancer in nz, colon cancer symptoms, colon cancer risks

Table of Contents

What is colon cancer?

Colon cancer occurs in your colon. The colon is the longest part of the large intestine. It is a type of bowel cancer or more specifically colorectal cancer, which can occur in either the colon or the rectum (rectal cancer).

 

Colon cancer typically begins as small polyps that form inside the colon on the bowel lining. A polyp is a small clump of cells; most colon polyps are harmless. However, these polyps can slowly change and turn into cancer over time.

Who gets colon cancer in New Zealand?

The rate of bowel cancer in New Zealand is very high, with over 3,000 New Zealanders diagnosed every year. It is estimated that 1 in every 18 New Zealanders will develop bowel cancer in their lifetime.

Men are slightly more likely to develop colon cancer than females. It typically affects people aged 50 years and older – however the rate of colon cancer in people aged 20 to 49 is increasing.

Colon cancer symptoms you should act on

Don’t ignore persistent bowel changes. The following symptoms should be addressed with a healthcare professional if they persist for more than a couple of weeks.

 

  • Blood in your poo or bleeding from your bottom.
  • Changes in your bowel habit (looser, more or less frequent, diarrhoea or constipation).
  • Stomach pain, discomfort, bloating and/or cramps.
  • Unexplained weight loss.
  • Fatigue (iron-deficiency/anaemia due to intestinal bleeding).
  • A feeling that the bowel doesn’t empty all the way during a bowel movement.

 

Being aware early is the best protection against colon cancer. If you notice lasting symptoms that worry you – at any age – It’s important to get checked by your doctor as soon as possible. Read more about bowel cancer symptoms here.

What are the risk factors of colon cancer?

There are both non-modifiable and modifiable risk factors for colon cancer. Non-modifiable risk factors that may increase your risk of colon cancer include:

 

  • Age: colon cancer develops mostly in people over 50 years, however rates are increasing in people between the ages of 20 to 49 too.
  • Family history: having two or more close relatives with bowel cancer increases your risk.
  • Inherited conditions: such as lynch syndrome or FAP (familial adenomatous polyposis) may increase your risk.
  • Inflammatory bowel disease: conditions like chronic ulcerative colitis and Chron’s colitis may increase risk of colon cancer.
  • Many polyps: people with more colon polyps often have an increased risk of colon cancer.

 

Modifiable or lifestyle risk factors for colon cancer include:

 

  • Smoking: Smoking increases the risk of colon cancer. Quitting brings health benefits at any age. This includes chewing tobacco, and vaping.
  • Excess alcohol: Studies show excess daily alcohol consumption increases the risk of colon polyps and raises general cancer risk.
  • Low-fibre diets may increase your risk of colon cancer as can cause inflammation and weaken the gut barrier, potentially increasing exposure to carcinogens.
  • High-fat and high-calorie diets can affect your weight, and obesity contributes to an increased risk of colon cancer.
  • Diets high in red meat and processed meat are also associated with higher risk.

How to lower your colon cancer risk?

While some risk factors for colon cancer are unavoidable (e.g., age or genes), making changes in everyday life can reduce your risk of colon cancer.

 

  • Eat more healthy, fibre-rich foods. Whole grains (e.g., brown rice, oats), vegetables and fruits have fibre, vitamins, minerals, and antioxidants.
  • Cut back on red and processed meats, high-fat foods, and high-calorie foods.
  • Drink in moderation. Don’t drink more than two drinks a day for men and one for women.
  • Stop smoking, talk to your pharmacist or doctor about smoking cessation support.
  • Exercise most days of the week, try to get at least 30 minutes of exercise.
  • Maintain a healthy weight, the adjustments above will help you achieve this.

How screening for colon cancer in New Zealand works?

New Zealand’s National Bowel Screening Programme is a free programme to help detect bowel cancer at an early stage. Bowel cancer often has no symptoms, so this testing helps find it early, when it often can be treated successfully. Here are the key details:

 

  • Currently offered every two years to people aged 60 to 74 who are eligible for publicly funded healthcare.
  • The starting age is being lowered to 58 in two stages, beginning in October 2025 and in place by March 2026.
  • When you become eligible you will be sent: an invitation letter, a consent form, a test kit, and instructions for the test kit.
  • You will continue to be sent a test kit every 2 years until you are 74 years old.
  • If you should be eligible and haven’t received a kit you can request one by contacting the programme, call: 0800 924 432 or email: info@bowelscreening.health.nz

How is bowel cancer treated?

A positive test result does not mean you have cancer, it is detecting traces of blood in your poo. Small amounts of blood in your poo can often be due to polyps or haemorroids.

 

You’ll be contacted by your healthcare provider to discuss your results and next steps. If your test is positive, you will likely need a colonoscopy. This is where a small camera is used to look at the lining of your large bowel (colon). A biopsy can be taken, and small polyps can be removed.

What happens after a positive colon (bowel) cancer test?

Treatments for colon cancer will depend on the stage of the cancer, its location, and whether it has spread. Treatments for colon cancer include:

 

  • Chemotherapy,
  • Immunotherapy,
  • Surgery,
  • Radiation treatment.

 

Before starting any treatment, make sure you have discussed and understood your treatment plan. Asking for a second (or third, etc.) opinion is always something to consider too.

Support and resources for colon (bowel) cancer

Bowel Cancer New Zealand (external link)

Bowel Screening (external link) Health New Zealand

Bowel Cancer (external link) Healthify

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