Bowel cancer awareness: Understanding your bowel

Your bowel (colon and bowel)

The bowel is a six-metre-long tube made of muscle, with a lining similar to the inside of the cheek. It is part of the digestive system and extends from the stomach to the rectum and anus. There are two parts of the bowel - the small bowel and the large bowel.

Cancer of the small bowel is rare.

The large bowel is made up of two parts - the colon and the rectum. Cancer of the large bowel is the most common cancer in New Zealand. If you have a family history of bowel cancer, talk to your doctor about your risk.

The digestive system

How the bowel works

Food and liquid is broken down in the stomach. It is then digested in the small bowel, before passing into the large bowel. Here water and some nutrients are absorbed, leaving waste. Waste passes through the rest of the large bowel before leaving the body when you go to the toilet.

Looking after your bowel

Some 'everyday' things you can do that may reduce your risk of developing bowel cancer are:

• be physically active every day for 30 minutes or more. (Walk instead of driving to the shops, use the stars.)
• aim to be a healthy weight throughout life. Weight gain, especially around the waist is linked to bowel cancer.
• eat mostly plant foods (vegetables, fruit, grains and pulses).
• choose wholemeal and whole grain breads and cereals.
• eat smaller and fewer servings of red and processed meats.
• eat foods low in fat, salt and sugar.
• if you choose to drink, limit alcoholic drinks to one drink for women per day and two drinks per day for men.
• don't smoke.

What you should look for

Early bowel cancer often has no symptoms

It is important to know what is normal for you so you can spot any changes. If you notice any of these symptoms and they last longer than four to six weeks, tell your doctor.

• Bleeding from your bottom or blood in your bowel motion.
• A recent change in your bowel motions: going to the toilet more often, diarrhoea, constipation or a feeling that your bowel does not empty completely.
• Stomach pains, frequent wind pains, bloating or cramps.

These symptoms may not be caused by cancer, but it is important to play it safe and talk to your doctor. 

In New Zealand, a bowel cancer screening programme (checking people who have no symptoms) is in the early stages of development. For more information, talk to your doctor or visit the National Screening Unit's website (www.nsu.govt.nz).

This information was published in April 2010 by the Cancer Society.