Risk factors for bowel cancer

The bowel is part of the body’s digestive system. It helps the body break down and absorb food and water and get rid of waste. The bowel is divided into the small bowel (or small intestine) and the large bowel. The large bowel includes the large intestine and rectum. Most bowel cancers arise from small growths (called polyps) that are on the lining of the wall of the large bowel.

Risk factors for bowel cancer include:

  • Aged over 50 years – your risk increases with age. But bowel cancer is rising among young people.
  • Ethnicity- Māori and Pasifika peoples are more likely to get bowel cancer at a younger age.
  • If you have an inflammatory bowel disease (IBD), such as Crohn's disease or ulcerative colitis.
  • A significant family or personal history of bowel cancer or polyps (a type of non-cancerous bowel growth called adenomas).
  • Some genetic conditions carried in families (e.g. Lynch syndrome).
  • Being overweight and not active.
  • Regularly eating large amounts of processed meat and red meat
  • Not eating enough fibre from grainy breads, cereals, fruit and vegetables
  • Drinking alcohol.
  • Smoking.

Having one or more of these risk factors does not mean that you will develop bowel cancer. Some people who get this disease may not have any known risk factors.


How you can lower your risk of bowel cancer

There is no certain way to prevent bowel cancer but there are some things you can do to lower your risk.

  • Have a free bowel screening test every two years (if you are 60-74 years). Bowel screening can find and treat early changes before they turn into cancer. Screening is for people who show no signs or symptoms of bowel cancer.
  • Eat a wide variety of nutritious foods low in saturated fat, salt and sugar.
  • Eat high fibre foods daily. Foods like fruit, vegetables, wholegrain bread, breakfast cereal, pasta, brown rice, beans, nuts and seeds.
  • If you eat meat, try to eat less than 350 to 500 grams of cooked red meat per week. Eat little, if any, processed meat such as bacon, sausages, luncheon, ham or salami.
  • Be a healthy weight.
  • It’s best not to drink alcohol. If you do, limit the amount you drink to two or less drinks per day.
  • Be active every day.
  • Not smoking.


Family history of bowel cancer

Anyone, including young people, with concerns about their risk of developing bowel cancer should talk to their doctor.

If you have a family history of bowel cancer, polyps or inflammatory bowel disease, you may need more regular checks. This may start at a younger age.

If you have any bowel cancer signs and symptoms (at any age)

See a doctor and get these checked out. Your doctor will arrange the right tests and treatment if you need it.  Please do not ignore them.


Signs and symptoms of bowel cancer may include:

  • bleeding from your bottom or blood in your poo
  • a change in bowel habits that last six weeks or more. These may be loose and runny poo or constipation.
  • stomach pain cramping or bloating that lasts 6 weeks or more
  • weight loss
  • unexplained tiredness or fatigue.

Many conditions can cause these symptoms, not just bowel cancer. If you have any of these symptoms, talk to your doctor. Please do not ignore them.