This booklet is for you if you have or someone close to you has Colon or Rectal Cancer.
If you are a patient, your doctor or nurse may wish to go through the booklet with you and mark sections that are particularly important for you.
The large bowel colon and rectum
The colon and rectum make up the large bowel, which is part of our digestive system. The colon is where water is absorbed as part of the digestive process and the rectum is where waste matter (stools or faeces) is held until it's ready to be passed.
About two-thirds of cancers that develop in the large bowel occur in the colon and one-third occur in the rectum.
The walls of the colon and rectum are made up of layers of body tissue. Most colon and rectal cancers start in the innermost lining of the bowel and develop from small growths called polyps.
Large bowel colon and rectum
Once food has been swallowed, it passes down the gullet (oesophagus) to the stomach, where digestion begins. It then passes through the small bowel, where essential nutrients are taken into the body. The digested food then moves into the colon, where water is absorbed. After the colon, the remaining waste matter, known as stools or faeces, is held in the rectum (back passage) until its ready to be passed from the body through the anus as a bowel motion (stool).
Close to the bowel are lymph nodes, also known as lymph glands, which are about the size of a baked bean. The lymph nodes are part of the lymphatic system.
The colon is divided into four sections:
The rectum is the last part of the large bowel before it opens to the outside at the anus. It is approximately 15cm long.
To help describe the position of a cancer within the rectum it is sometimes divided into three sections upper, middle and lower. The upper rectum is the section directly after the sigmoid colon, and the lower rectum is where the large bowel joins the anus.