Colonoscopy: When to have one and what to expect

If your doctor refers you for a colonoscopy, here’s what you need to know about the procedure.

What is a colonoscopy?

A colonoscopy is a procedure where a doctor looks inside your large and small intestines to check for problems like polyps, colorectal cancer, and digestive issues.

What happens during a colonoscopy?

A colonoscopy is an examination of the colon (large intestine) performed by a doctor trained in endoscopy, such as a gastroenterologist, surgeon, or physician. It’s the best way to detect, diagnose, and treat various digestive issues, including colorectal cancer, which is one of the top three cancers in South Africa.

Reasons to have a colonoscopy

Professor Christo van Rensburg, a gastroenterologist at Mediclinic Louis Leipoldt, says the three main reasons to perform a colonoscopy are for screening, diagnosis, and therapy.

1. Screening colonoscopy is done to find and remove polyps in the colon. Polyps are growths inside the colon. Some are harmless, but as they grow, they can turn into cancer, since all colon cancer starts from polyps.

“Screening colonoscopy is done as a preventative measure against colon cancer for patients who don’t have specific complaints. Ideally, men and women over age 50 without a direct family history of colon cancer should have one,” says Professor Van Rensburg. “Cancer associations around the world encourage the use of screening colonoscopy. It’s an effective way to prevent and detect colorectal cancer.”

If your colonoscopy results are normal, you only need another one in five to ten years, he advises

If you have a family history of colon cancer, you should have your first colonoscopy 10 years earlier than the age your relative was diagnosed. For example, if your mother had colon cancer at 50, you should get a colonoscopy at around 40.

People with rare inherited conditions that cause polyps in the digestive system should have colonoscopies much earlier.

2. “Diagnostic colonoscopy is done to find a disease or a disease process in patients with symptoms like unexplained weight loss, changes in bowel habits, bleeding from the rectum, iron deficiency, anaemia, or chronic diarrhoea,” Professor Van Rensburg says.

3. Therapeutic colonoscopy is used to treat conditions in the lower digestive system. This can include procedures like banding haemorrhoids, removing cancerous or pre-cancerous tissue, or using laser therapy to stop bleeding and shrink tumours.

What happens during a colonoscopy?

A colonoscopy involves a flexible tube (colonoscope) being inserted into your rectum. The colonoscope has a camera and light to examine the inside of your colon. It is moved through the colon, and if any polyps are found, they can be removed using a special tool. The doctor may also use forceps to take samples or give injections.

Professor Van Rensburg explains that a good colonoscopy requires proper preparation to ensure clear images. You’ll be given up to two days to clean out your bowels with the aid of a laxative You’ll also need to follow a low-fibre diet, mostly soft or liquid foods. You may need to stop taking blood-thinning medications two days before the procedure to reduce the risk of bleeding.

Is colonoscopy safe?

"During the procedure, the patient is given a mild sedative, so they are relaxed but still awake and breathing on their own. Air is pumped into the colon to get a clear view, or sometimes carbon dioxide is used to reduce bloating and cramps afterwards. The procedure usually takes 30 to 60 minutes, depending on what is found, whether polyps need to be removed, or if biopsies are taken," explains Professor Van Rensburg.

The removed polyps or biopsied tissues are then sent for histological analysis to identify any abnormalities or diseases.

“A colonoscopy is a fairly safe procedure,” Professor Van Rensburg says, although there may be adverse effects afterwards like cramps, possibly bleeding, or nausea and vomiting from the anaesthetic. These may last from a few hours to a few days. You should not drive for 24 hours after the procedure because of the sedation.

• Remember, if cancer is found early, it’s often treatable. Don’t put off your screening tests.
• To book a colonoscopy, contact our Mediclinic Engagement Centre via WhatsApp 087 240 6367 or click here for alternative contact options: