Colorectal cancer Dr Rob Hicks and Dr Trisha Macnair It may not make the headlines as much as breast or lung cancer, but colorectal is the third most common type of cancer in the UK. With early diagnosis it is one of the most treatable.

In this article

What is colorectal cancer? Symptoms

Causes and risk factors Diagnosis and treatment

Further information

Colorectal cancer (also known as bowel cancer) affects the lower part of the digestive system - the large bowel and the rectum. It affects men and women equally, and is the third most common type of cancer in men and the second most common in women. One in twenty people in the UK will develop bowel cancer in their lifetime.

The condition is rare in people under 40 and almost 85 per cent of cases are diagnosed in over 65 year olds.

Each year, more than 35,000 people are diagnosed with bowel cancer and about 16,000 die as a result of the disease. If caught early, this cancer can be treated effectively, and survival has doubled over the last 30 years because of early diagnosis. so the chances of being cured are increased if people are aware of the symptoms and go to their GP as soon as possible

The symptoms of bowel cancer are very similar to common complaints such as piles or irritable bowel syndrome. You should see your GP if you see:

• Blood flecks in your stools, particularly if the blood is dark or plum-coloured. This is the most commonly noticed symptom and should never be ignored.
• A change in your regular bowel habits, such as constipation or diarrhoea, that's severe or lasts for two weeks or more.
• Abdominal pain or discomfort that lasts for two weeks or more.
• Unexplained weight loss.

Some people feel tired, dizzy or breathless because they've become anaemic from microscopic bleeding from the bowel. For others, the first sign of a problem is bowel obstruction with constipation, severe abdominal pain, vomiting and often a swollen abdomen.

The exact cause of bowel cancer isn't known, but a family history of the condition can increase your risk. If you have a first-degree relative (a member of your immediate family) diagnosed before the age of 45 or two immediate family members affected by the disease, you should talk to your GP about genetic screening to see if you're at risk. Keep a record of your family health history.

Your risk of colorectal cancer increases with age - the average age of diagnosis is about 70. However, younger people can also be diagnosed.

Previous problems with chronic inflammatory bowel disease, such as long standing ulcerative colitis and Crohn's disease also appear to increase the risk of this type of cancer.

Bowel cancer screening

The government has introduced the NHS bowel cancer screening programme. It offers routine screening every two years to all men and women aged 60 to 69 (50 to 74 in Scotland). People over 70 can request a screening kit by calling a freephone helpline when the programme reaches their area.

To diagnose bowel cancer, your GP may do a rectal examination with a gloved finger to feel for any lumps or swellings.

Your GP may need to refer you to hospital for treatment.

At the hospital the specialist may suggest various tests, including a colonoscopy or sigmoidoscopy. Both involve gently pushing a long thin tube containing a tiny video camera through your back passage and into the rectum and colon to take a close look at the inside of the bowel. If polyps or abnormal areas of the lining of the bowel are seen, biopsies may be taken and sent to the laboratory for analysis. A barium enema may also be done.

If the diagnosis is cancer, the tumour will then be 'staged'. This will involve more complex tests such as scans (CT – Computerised Tomography and MR – Magnetic Resonance). This process, used with many cancers now, involves assessing how far the tumour has grown and spread. It helps doctors to work out what treatment is most appropriate and can provide an estimate of the chances of it a cure.

The main treatment is surgery. Usually, the piece of bowel that contains the cancer is removed and the two open ends are joined back together.

If the two sections can't be joined back together, often because the tumour is too low, the bowel can be brought out through the abdominal wall. This is called a stoma, which is connected to a colostomy bag. Although this procedure is more likely after removal of a tumour in the rectum, it's not always necessary and may only be temporary.

Chemotherapy and radiotherapy are increasingly being used to treat bowel cancer in addition to surgery as an additional helping treatment, especially in more advanced tumours.

For example, a combination of radiotherapy and chemotherapy may be given before surgery for rectal cancer. This is known as neo-adjuvant therapy, and it may reduce the risk of recurrence and improve survival rates.

How well patients do after treatment depends on the stage that the cancer has reached. Survival rates have improved in the past 30 years but overall survival is still only about 50 per cent at five years. However, when bowel cancer is caught early - before it has spread to other organs such as the liver or the lungs - the chances of recovery are high, more than 80 per cent.

Prevention

A high-fibre diet with plenty of fruit, vegetables and carbohydrates (pasta, bread, rice) is believed to reduce the risk of colorectal cancer.

Eating a diet high in saturated fat and red meat, and low in fibre, smoking and being overweight increases your risk.

Eating at least five portions of fruit and vegetables every day is thought to protect against this and many different cancers through the benefits of the antioxidant vitamins and minerals they contain.

For more information about nutrition and how to follow a healthy diet see Nutrition.

Moderate amounts of exercise may also protect against bowel cancer.

NHS cancer screening programme
Website: www.cancerscreening.nhs.uk

Scottish Bowel Screening Programme
Website: www.bowelscreening.scot.nhs.uk

Bowel Cancer UK
Website: www.bowelcanceruk.org.uk

British Colostomy Association
Website: www.colostomyassociation.org.uk

CORE - Digestive Disorders Foundation
Website: www.digestivedisorders.org.uk

This article was last medically reviewed by Dr Brian Haylock in March 2009.
First published in February 1999.