What Is a Colonoscopy?
A colonoscopy is a camera examination of your large bowel — the colon and rectum. A thin, flexible tube (called a colonoscope) is gently passed through the anus while you are sedated, so you won't be aware of or remember the procedure. The camera lets your doctor look directly at the lining of the bowel, take small tissue samples (biopsies) if needed, and remove any polyps — small growths — on the spot. The whole thing takes about 20 to 45 minutes and you go home the same day.
Who Definitely Needs a Colonoscopy?
Some situations make a colonoscopy clearly the right next step. You should see your GP about a referral if any of the following apply to you:
- A positive faecal occult blood test (FOBT) — this is the bowel cancer screening test sent out by the National Bowel Cancer Screening Program; a positive result means blood was detected in your stool and needs to be investigated
- Rectal bleeding or blood in your stool
- A noticeable change in your bowel habit that has lasted more than four to six weeks
- A family history of bowel cancer in a first-degree relative — that's a parent, sibling, or child
- A personal history of bowel polyps (growths) that need to be checked again
- Symptoms that might suggest inflammatory bowel disease — things like blood or mucus in the stool, frequent urgency, or persistent cramping
- Iron deficiency anaemia (low iron in your blood) without a clear explanation
- Unexplained weight loss alongside bowel symptoms
Any rectal bleeding — blood on the toilet paper, in the bowl, or mixed through your stool — should be checked by a doctor. Please don't assume it's haemorrhoids without having it properly looked at. Most of the time it will turn out to be something straightforward, but it's important not to leave it uninvestigated.
Screening Colonoscopy — Who and When?
If you have no symptoms and no family history of bowel cancer, you're considered average risk. For average-risk Australians, the National Bowel Cancer Screening Program offers a free FOBT (faecal occult blood test — a simple home test kit) every two years from age 45. If your FOBT comes back positive, a colonoscopy is the required next step. If you've already had a colonoscopy with polyps removed, your follow-up interval will depend on what was found — Mr Nguyen will give you a specific recommendation.
Family History Guidelines
If someone in your close family has had bowel cancer, your starting age for colonoscopy screening may be earlier:
- One first-degree relative diagnosed with bowel cancer at any age: colonoscopy from age 40–45, or 10 years before the age your relative was diagnosed — whichever is earlier. Repeated every 5 years if clear.
- One first-degree relative diagnosed under age 55, or two or more first-degree relatives with bowel cancer: colonoscopy from age 40 (or 10 years before the earliest diagnosis in your family), and repeated every 3–5 years
- A strong family history or a known hereditary condition such as Lynch syndrome or FAP (familial adenomatous polyposis): you'll need specialist input to set up a personalised surveillance plan — please ask your GP for a referral
What Does Colonoscopy Involve?
Preparation
In the days before your colonoscopy, you'll follow a low-residue diet — foods that are easy to digest and leave little behind in the bowel. On the day before, you'll drink a bowel preparation solution that clears everything out. It's the most unglamorous part of the whole process, but it really matters — a clean bowel means a better and more accurate examination. Our rooms will give you detailed written instructions.
The Procedure
The colonoscopy itself is done under conscious sedation — sometimes called twilight anaesthesia — so you'll be comfortable, relaxed, and most likely remember very little of it. A thin, flexible tube with a camera at the tip is gently passed through the anus and guided around your colon. If any polyps (small growths) are found, they're removed right then and there, in the same procedure. The whole thing takes 20 to 45 minutes.
Recovery
After the procedure, you'll spend about one to two hours in the day surgery recovery area while the sedation wears off. You'll need someone to drive you home — you can't drive yourself after sedation. Most people feel completely back to normal by the same evening, and you can eat and drink normally straight away.
Frequently Asked Questions
For most people, the honest answer is no. The sedation means you won't be aware of what's happening, and most patients have no memory of the procedure at all. You might notice some mild bloating or wind afterwards — this is from the gas used to inflate the bowel during the examination — but it settles within a couple of hours. Many people are genuinely surprised by how easy the experience is.
Finding a polyp is actually good news in a way — it means the colonoscopy found something that can be dealt with before it causes any harm. Polyps are removed during the same procedure using a wire loop (called a snare), so there's no need for a separate operation. The removed tissue is sent to the laboratory to be examined under a microscope. Depending on what type of polyp it was, you'll be given a recommendation for a follow-up colonoscopy at the appropriate time.
Colonoscopy is a very safe procedure. The main risks to be aware of are a small chance of a tear in the bowel wall — called perforation — which happens in fewer than 1 in 1,000 procedures, and a small risk of bleeding after polyp removal (under 1%). Your surgeon will talk you through these before you sign the consent form. For most people, the benefit of finding or ruling out bowel problems far outweighs these small risks.
Yes — you'll need a referral from your GP to see Mr Nguyen and arrange a colonoscopy. If your FOBT result was positive, please ask your GP for an urgent referral. Don't put it off.
Learn more about this procedure — including what to expect, benefits, risks, and recovery.
Procedure details →Still not sure whether a colonoscopy is the right next step for you?
A short consultation with Mr Ba Nguyen at North Eastern Surgical will clarify whether you need the test now, whether you can rely on the FOBT, or whether a different investigation is more appropriate. Ask your GP for a referral or call our rooms on (03) 9816 3951. Request an appointment →