Cheshire Gut and Liver Clinic
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Bowel cancer is now the second most common type of cancer with 35,000 new diagnoses and more than 16,000 deaths from the disease each year.
On average, there is approximately a 1/20 lifetime risk of developing the disease. However, if caught early it can nearly always be cured, sometimes even without the need for surgery.
What are the symptoms of bowel cancer?
Early bowel cancer may give no symptoms at all. Some of the classical symptoms, however, are:
-blood seen on or mixed in with stool or in the toilet pan
-a change in bowel habit - to more frequent bowel actions or occasionally constipation
-tiredness or shortness of breath from anaemia due to blood loss into the bowel
-a persistent lump in the abdomen
Abdominal pain in isolation is rarely due to bowel cancer and many of the symptoms listed above are commonly due to less serious benign conditions such as piles, diverticular disease or irritable bowel syndrome. However new symptoms should always be discussed with your GP who can advise on whether further investigation or screening for bowel cancer is indicated.
Who is at risk?
The simplest answer to this question is everyone over the age of 50 years. Cancer is unusual before the age of 50, but younger patients with symptoms should always be checked carefully as 7% of colon cancers occur before 50, and a few at a very early age. Some patients are at higher than average risk for bowel cancer so need more regular check ups starting at an earlier age. These include those with a family history of bowel cancer or polyps, those who have had polyps previously and patients with total colitis who have had their disease for 8 years or more. If in doubt discuss your family history or personal disease history with your family doctor. For those with a family history of colon and other cancers, advice from a geneticist may be useful in estimating risk and establishing an effective surveillance programme.
How does bowel cancer happen?
Nearly all bowel cancers start as polyps. These are small benign growths, a bit like warts, on the inside of the bowel wall which grow slowly. Eventually some polyps turn into cancers which can then invade into the bowel wall and spread to other parts of the body. The natural history of the development of bowel cancer means it is ideal for a screening and cancer prevention programme because most polyps develop into cancers very slowly over a 10-20 year time period so there is a “window of opportunity” to find and remove them and prevent cancer. Removing polyps reduces the risk of colon cancer by about 80%.
Even if cancer has occurred, if caught early, it is nearly always curable. 85% of people treated at stage A will survive the next 5 years, whereas if the diagnosis is made late, at stage C, less than 50% will survive.
What can I do to reduce my risk of colon cancer?
General health advice applies equally to bowel cancer prevention:
-eat a balanced diet, reducing animal fat intake particularly from red meat
-exercise to keep the heart and chest healthy reduces risk of colon cancer
-keep your weight down
-above all don’t smoke
-have any symptoms checked out promptly
-have a screening procedure
What are the options for bowel cancer screening?
There are numerous modalities to carry out bowel cancer screening but colonoscopy is the gold standard examination for the large bowel and is now widely established in the USA as the recommended bowel cancer screening investigation. It involves inserting a long, flexible endoscope all the way around the colon to directly visualise all areas where polyps and cancer can occur. Again it is critically dependent on the operator and the equipment. You would need to take a full bowel preparation the day before colonoscopy so that the colon is clean and views are optimised. If you are constipated you may need more laxatives to cleanse the colon. The procedure is carried out in the Endoscopy Unit and patients are offered sedation if they want it, though at least 50% of people can have colonoscopy without. The advantages of unsedated colonoscopy are an immediate return to normal life and the avoidance of unnecessary drugs.
Modern video endoscopes give high definition colour images which are superior to looking directly at the bowel wall with the naked eye. If polyps or cancer are detected they can be biopsied or removed, so colonoscopy is definitive, combining diagnosis with treatment in one procedure. Colonoscopy is highly sensitive and specific for cancer and polyps but does carry a small risk of complication, mainly from removing polyps or early cancers from the bowel wall. It is also highly operator dependent, in that the comfort, accuracy and risk of the procedure is directly related to the skill and experience of the doctor performing it.
Which is the best screening test for me?
In the USA bowel cancer screening by colonoscopy has been established since 2000 with the recommendation that average-risk individuals are screened every 10 years from age 50 by colonoscopy. Incidence rates of bowel cancer in certain patient groups are now falling in the USA suggesting that screening is having a positive overall impact.
How can I know the doctor I will see is an expert at colonoscopy?
Standards of colonoscopy do vary from centre to centre and from doctor to doctor. In expert hands the procedure should be comfortable, safe and complete and sedation can be kept to a minimum which makes the procedure inherently safer and quicker. Within the NHS there is now a process of accreditation of colonoscopists to perform the procedure in the screening setting. Doctors passing the accreditation test have a major focus on colonoscopy in their working practices and have proved their knowledge and hand-skills to their peers.
If you are having a colonoscopy don’t be afraid to ask the doctor performing the procedure the following questions:
-How many colonoscopies have you performed in your career?
Most experts will have performed thousands of examinations
-How often do you get all the way around the colon?
This should be at least 90%
-Have you ever had any major complications and how often have they occurred?
Perforation should be <1:5000
-Are you accredited to perform screening colonoscopy in the NHS?
A colonoscopist will need to be accredited by National Bowel Cancer Screening Programme in order to perform screening colonoscopy in patients involved in the Bowel Cancer Screening Programme
Dr Kevin Yoong is a Consultant Gastroenterologist and Colonoscopist accredited by the National Bowel Cancer Screening Programme.
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