What is colonoscopy?
Colon cancer is the largest cause of death from cancer in men who don't smoke, and 2nd largest cause in men who do smoke, and in women. But most colon cancers can now be prevented. Colonoscopy is the best and only way to do it! It also helps discover, monitor and treat other diseases of the colon.

The colon is another name for the large bowel. While the back passage and the lower parts of the colon can be viewed directly using small metal or plastic tubes, other methods are needed to inspect the rest of the bowel. This is usually done by a barium enema X-ray or by colonoscopy.

Since all colon cancers come from polyps, we aim to find polyps early through the colonoscope and remove them before they turn into cancer, i.e. cancer prevention. A polyp looks like a wart or cherry. Routine colonoscopy prevents cancers by removing polyps.

The Scope
The new technology we use is the video colonoscope. It has a video chip in its tip, which transmits visual images to a television monitor. Using controls at the head of the instrument we can bend the tip through about 360° so we can see around corners. There are channels for injecting air, for sucking out gas and fluid, and a windshield washer to clean the tip of the instrument for good visibility.

Another channel allows us to insert forceps to take a bite out of a lesion and a snare to remove a polyp. This is making good use of new and, unfortunately, fairly expensive technology. The cramps or fullness that occur during the procedure last only a few seconds and occur as we progress around a corner. Compared to the ravages of colon cancer, this amount of discomfort is certainly worth it!

Who has a colonoscopy?
A colonoscopy may be advised if you have symptoms such as bleeding from the anus, pains in the lower abdomen, persistent diarrhoea, or other symptoms thought to be coming from the colon. The sort of conditions which can be confirmed include:

• Ulcerative colitis (which causes inflammation of the colon).
• Crohn's disease (also causes inflammation of the colon). 
• Diverticula (pouches which form in the lining of the colon). 
• Polyps of the colon. 
• Cancer of the colon.

Various other conditions may also be detected. Also, a colonoscopy is often normal. However, a normal result may help to rule out certain possible causes of your symptoms.

What happens during the examination?
On the day before the examination, the patient will be given a laxative to ensure the bowel is empty. Nothing to eat or drink is allowed for six hours before the procedure.
Colonoscopy is done on an outpatient basis and takes about 20 to 40 minutes. A sedative is injected into a vein to induce a sleepy and relaxed feeling while the examination is carried out.

The person will be asked to lie on their side during the examination.

The colonoscope will be lubricated with some jelly and gently inserted into the bowel through the back passage. Some air may be blown gently into the bowel to improve the view of the bowel lining. This can make the person being examined want to pass wind but it is important not do so, until the doctor has all the pictures and samples needed.
Many doctors now prefer to watch the images from the colonoscopy on a TV screen next to the patient rather than look directly down the colonoscope, and patients are often allowed to view this if they want to.

Sometimes the doctor will need to take small samples of tissue. This is completely painless. This tissue is sent to the laboratory for specialised inspection and the results should be ready after a few days.

Afterwards, the patient will be allowed to doze until the effects of the sedation wear off before going home.

If a larger piece of tissue, such as a polyp, has been removed, it may be necessary to stay in the hospital for a few hours for observation for possible bleeding. Patients will not be able to drive home because of the sedation.

What preparation do I need to do?
You should get instructions from the hospital department before your test. The sort of instructions given include:

• The colon needs to be empty so that the operator can get a clear view. You will be instructed on how to take a special diet for a few days before the test. You will also be given some laxatives to take.
• You will need somebody to accompany you home, as you will be drowsy with the sedative.

Are There Any Complications?
Colonoscopy is safe and is associated with very low risk when performed by physicians who have been trained and are experienced in this procedure.

Complications can occur, but they are rare. Local discomfort usually disappears at the end of the procedure. Bleeding may occur from the site of biopsy or polyp removal. Perforation (a small hole in the lining of the bowel) may also occur rarely. These complications are usually mild but rarely may require blood transfusions or surgery.

After Your Procedure
If you were sedated for the procedure, you cannot drive until the following morning and must arrange to have someone else drive you home after the procedure. If you choose to go by taxi or public transit, you must be accompanied by someone.
For safety reasons, the person who drives or accompanies you must meet you inside the clinic after the procedure. You cannot leave the clinic on your own.

What can I expect after a colonoscopy?
Most people are ready to go home after resting for half an hour or so. You may need to stay a bit longer for observation if you have had any polyps removed.

If you have had a sedative - you may take a bit longer to be ready to go home. The sedative will normally make you feel quite pleasant and relaxed. However, you should not drive, operate machinery or drink alcohol for 24 hours after having the sedative. You will need somebody to accompany you home and to stay with you for 24 hours until the effects have fully worn off. Most people are able to resume normal activities after 24 hours.

The operator writes a report and sends it to the doctor who requested the colonoscopy.

The result from any biopsy may take a few days which can delay the report being sent.

The operator may also tell you what they saw before you leave. However, if you have had a sedative you may not remember afterwards what they said. Therefore, you may wish to have a relative or close friend with you who may be able to remember what was said.

Are there any side-effects or complications from having a colonoscopy?
Most colonoscopies are done without any problem. The sedative may cause you to feel tired or sleepy for several hours afterwards. You may pass a small amount of blood from your anus if a biopsy was taken, or if a polyp was removed.

Occasionally, the colonoscope may cause damage to the colon. This may cause bleeding, infection and, rarely, perforation. If any of the following occur within 48 hours after a colonoscopy, consult a doctor immediately:

• Abdominal pain. (In particular if it becomes gradually worse, and is different or more intense to any 'usual' pains that you may have.)
• Fever (raised temperature). 
• Passing a lot of blood from your anus.