What is bowel cancer?

Bowel cancer, also known as colorectal cancer, is a potentially fatal mutation of cells in the lower part of the body's digestive system.

The digestive system is made up of several stages. After food is swallowed, it passes into the stomach. The food is digested and passes into the small bowel.

The food continues into the large bowel. Waste matter accumulates in the rectum until it is ready to be passed out of the body in a bowel motion.

Bowel cancer affects these last two parts of the digestive system - the large bowel and the rectum.

There are several factors which put someone at greater risk of developing the disease.

Familial adenomatous polyposis (FAP) is a rare disease that runs in families. It causes small non-cancerous growths known as benign polyps to develop in the bowel. Over time these can develop into cancer.

A strong family history of bowel cancer is also a risk. A strong family history is defined as three close relatives who have had bowel cancer.

These relatives must be in at least two different generations of the family, and at least one of these relatives must have been under 50 years old when they were diagnosed.

A bowel disease called ulcerative colitis can cause bowel cancer in the long term.

What are the symptoms?

Doctors and public health officials encourage people to be familiar with the symptoms of the disease because early diagnosis means the difference between life and death.

The symptoms of bowel cancer can be:

• Fresh blood in the stools

• Lasting change in normal bowel habits, diarrhoea or constipation for example

• Weight loss

• Pain in the abdomen or rectum

• Strained feeling in the rectum

The cancer also commonly causes anaemia.

It can also cause a blockage, which is called a bowel obstruction. The symptoms of this are:

• Being sick

• Constipation

• Feeling bloated

• Griping pains in the abdomen

All these symptoms can also be caused by other diseases, but rectal examination and a biopsy, where a pathologist screens a small piece of tissue from the bowel, can give a more accurate diagnosis.

What is the outlook?

This depends entirely on how early the cancer is discovered. If it is caught early it is easily treatable.

There are three treatments for bowel cancer:

• Surgery, where the cancer is physically removed

• Radiation therapy, where powerful x-rays or other high-energy rays kill the cancer cells

• Chemotherapy, where drugs are used to kill the cancer cells

However, the success of treatment will be affected by the stage of the cancer and whether or not the disease has spread around the body.

There are six types of bowel cancer, which are known as stages.

Stage 0 is also known as carcinoma in situ. It is very early cancer and the cancer is found only in the innermost lining of the large bowel.

At stage I the cancer has spread further and involves the inside wall of the large bowel, but has not spread outside the colon.

Surgery can get rid of the cancer at these stages.

Cancer spreads outside the large bowel to nearby tissue at stage II. However, it does not yet affect any lymph nodes.

These are small, bean-shaped structures that are found throughout the body. They produce and store cells that fight infection.

They are invaded in stage III, which is when the cancer spreads to neighbouring nodes.

A combination of treatments may be required for stage II and stage III cancer.

Cancer spreads to other parts of the body in stage IV, and treatment may consist of complicated surgery on the bowel, the cancer itself and other organs.

Recurrent bowel cancer is when the cancer returns after it has been treated. It may come back in the large bowel or in another part of the body, and is often found in the liver and lungs.

Treatment will depend on where the cancer recurs, but is likely to involve a combination of surgery, radiotherapy and chemotherapy.

Is there help?

The British Digestive Foundation (BDF) funds research into digestive diseases and helps sufferers with practical guidelines on controlling symptoms.

The foundation is based at 3 St Andrews Place London NW1 4LB and can be contacted on 0171-486 0341.

A UK government campaign in association with The Crocus (Colo-Rectal Cancer Understanding and Screening) Trust has produced a leaflet, Don't Sit On Your Symptoms - Find Out About Bowel Cancer.

To get a free copy call the Department of Health on Freephone 0800 555777.