What is a colonoscopy, and why is it important?

Colorectal cancer is the #1 cancer in Singapore.

A large majority of cases can be prevented with early detection through a Colonoscopy

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5000+ scopes performed

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What is a colonoscopy?

A colonoscopy is a minimally invasive procedure that is used to examine the inner lining of the large intestine (colon), and rectum. It is performed using a long, flexible tube called a colonoscope, which has a tiny camera, and light at its tip. This device allows the specialist to visualise the colon in real time, identify abnormalities, and carry out interventions such as biopsies or polyp removal during the same session.

Colonoscopy plays a vital role in both the prevention, and early detection of colorectal conditions, including colon cancer. It is commonly used to investigate gastrointestinal symptoms, screen for colorectal cancer or monitor individuals with a personal or family history of colon-related diseases.

How does a colonoscopy work?

A colonoscopy is usually performed on an outpatient basis under light sedation to ensure comfort. The patient lies on their side while the colonoscope is gently inserted through the rectum, and guided along the entire length of the colon. The high-definition visuals captured by the camera are transmitted to a monitor, allowing the doctor to examine the colon lining in detail.

To ensure visibility, air or carbon dioxide is introduced to gently expand the colon. If abnormalities such as polyps, ulcers or bleeding areas are found, they can be treated or sampled immediately using specialised instruments passed through the colonoscope.

Additionally, the procedure typically takes 20 to 45 minutes, and most patients recover quickly afterwards with minimal discomfort.

When do you need to undergo a Colonoscopy?

Generally, if you're 50 or older and asymptomatic, a colonoscopy becomes part of your health maintenance routine. In Singapore, national guidelines recommend starting colorectal cancer screening at age 50, typically via annual FIT tests, with colonoscopies every 5–10 years depending on your risk and results.

That said, if you have personal or family risk factors – like a first-degree relative diagnosed with colorectal cancer, inflammatory bowel disease, your screening timeline should be accelerated. In these scenarios, doctors may advise starting earlier, often 10 years before the age at which your relative was diagnosed, or around age 40, whichever comes first.

If you're experiencing symptoms such as iron‑deficiency anaemia, unexplained weight loss, persistent stomach pain, blood in your stool, or changes in bowel habits, don’t wait to hit 45 or 50. If two or more of these symptoms are present, a colonoscopy may be warranted as a diagnostic necessity rather than a routine screening test.

The following symptoms are usually signs of colon cancer.

However, it is important to note that more than 50% of colon cancer cases present no symptoms.

Abdominal Discomfort

Frequent bloating

Recurring constipation

Rapid weight loss

Recurring diarrhoea

Unusual stool colour

Bleeding when passing motion

Any changes in bowel movement

If you are experiencing the symptoms,

consult a medical professional immediately.

Schedule an appointment with Dr Aaron Poh.

book an appointment

What conditions can a colonoscopy detect or treat?

Generally, a colonoscopy is a powerful tool used to diagnose, monitor, and treat a range of conditions, such as:

Colorectal cancer and polyps — early detection, and removal of precancerous polyps significantly reduce the risk of cancer.
Anaemia of unknown cause — often due to chronic blood loss in the gastrointestinal tract.
Chronic diarrhoea or constipation — to identify underlying causes.
Inflammatory bowel disease (IBD) — including Crohn’s disease, and ulcerative colitis.
Rectal bleeding or blood in stools — to identify the source, and manage bleeding.
Unexplained abdominal pain or bloating — to rule out structural abnormalities.

Why would I need a colonoscopy?

Patients may be recommended to undergo a colonoscopy for several key reasons. This may include:

Screening – routine screening is advised for individuals aged 50 years old, and above or earlier for those with a family history of colorectal cancer.
Diagnosis – if you present with persistent gastrointestinal symptoms such as rectal bleeding, changes in bowel habits or unexplained weight loss.
Surveillance – for those with previous polyps, colorectal cancer or chronic IBD.
Treatment – minor interventions such as polyp removal or bleeding control can be performed during the procedure.

What happens at a colonoscopy appointment?

We understand that for most patients, undergoing a colonoscopy can be a daunting experience. That is why we believe in the importance of ensuring all patients thoroughly understand what to expect before, during, and after a colonoscopy. In doing so, it will help reduce anxiety, and ensure a smooth experience.

Here is a step-by-step overview of what typically happens at each stage of the process:

Before the procedure: Preparing your bowel for examination

Preparation is key to a successful colonoscopy. A clean colon allows the doctor to view the lining clearly, and spot any abnormalities. Prior to the procedure, you can expect the following guidelines:

You will be advised to follow a low-fibre diet a few days before the procedure.
A prescribed bowel preparation (laxative) will be taken the day before to empty your colon.
Most procedures are performed under sedation, so you will need to fast for several hours beforehand.
Arrange for someone to accompany you home after the procedure, as the sedative can cause drowsiness.

During the procedure: What to expect in the endoscopy suite

The procedure is usually done in a day surgery or outpatient clinic. You will be made as comfortable as possible throughout, before the following steps are taken:

Step 01

You will lie on your left side on the procedure table

Step 02

A sedative will be administered via an intravenous (IV) line to ensure a relaxed, pain-free experience.

Step 03

The doctor will gently insert the colonoscope through the anus, and guide it through the colon.

Step 04

The colon lining is examined on a monitor, and biopsies or polyp removal may be done if needed.

After the procedure: Recovery and going home

Most people recover quickly after a colonoscopy, and can return to normal activities within a day. However, you can expect to:

Spend a short time in a recovery area until the sedative wears off.
Feel mild bloating or cramping, but this usually passes within a few hours.
Resume your usual diet, and activities the following day unless advised otherwise by our doctor.

Schedule Your Colonoscopy with Dr Aaron Poh.

What results can I expect?

Your colonoscopy results will depend on what is observed during the procedure. Once the procedure is completed, Dr. Aaron Poh will carefully review the findings, and explain them in detail. Afterwards, you will be informed of any abnormalities detected, and whether follow-up treatment is required.

Generally, the common outcomes of the procedure are:

RESULTS	FINDINGS	WHAT IT MEANS	NEXT STEPS
Normal Colon	If no abnormalities are found, the colon is considered healthy and free from signs of inflammation, polyps or cancer.	You may not need another colonoscopy for another 4 to 5 years, depending on your age, risk factors, and family history.	Continue routine health screenings, and maintain a healthy lifestyle to support colon health.
Polyps Detected	Polyps are small growths on the inner lining of the colon. While most are harmless, some can develop into cancer over time if left untreated.	The polyps will usually be removed during the colonoscopy, and sent to the lab for a biopsy to determine their type, and whether they are benign, pre-cancerous or cancerous.	Based on the number, size, and type of polyps found, Dr Poh will recommend when your next colonoscopy should be scheduled.
Other Abnormalities or Lesions Found	Sometimes, the colonoscopy may reveal ulcers, inflammation, diverticula (small pouches) or suspicious-looking masses.	These findings may point to conditions such as colitis, diverticular disease or colorectal cancer. Biopsies may be taken during the procedure for further analysis.	Depending on the diagnosis, additional investigations (such as imaging scans, blood tests or specialist referral) or a tailored treatment plan may be recommended.

How many sessions do I need?

In most cases, only one colonoscopy is needed for diagnosis or screening. However, if polyps are removed or if surveillance is required for conditions like IBD or a history of polyps, repeat colonoscopies may be scheduled at regular intervals. However, the frequency will be tailored based on your individual risk profile, and findings.

Book An Appointment

Undergoing a colonoscopy may feel daunting, but it is one of the most effective ways to detect early signs of colorectal conditions, including cancer, when they are most treatable. Whether you are experiencing symptoms or simply due for routine screening, taking a proactive step can make a significant difference to your long-term health.

At our clinic, Dr Aaron Poh, is here to support you with care in a safe, and comfortable environment. He prioritises clear communication, compassion, and personalised treatment plans that meet your unique needs.

If you have been putting off a colonoscopy or have questions about the process, do not wait. Remember: early detection saves lives. So, book a consultation (link to contact us page) with us today to safeguard your health for tomorrow.

Frequently Asked Questions (FAQs)

Is a colonoscopy painful?

Most patients report little to no pain due to the use of sedation. You may experience some mild bloating or cramping afterwards, but this is temporary, and usually subsides within a few hours.

What happens if a polyp is found?

Most polyps are benign, and removed during the same procedure. They are sent for biopsy to rule out cancer or pre-cancerous changes.

What are the possible risks or complications?

Colonoscopy is generally very safe, especially when performed by experienced specialists like Dr Aaron Poh. That said, potential risks include:

Mild bleeding, especially if a biopsy or polyp removal is performed.
Perforation (tear) in the bowel wall. However, this is rare, occurring in fewer than 1 in 1,000 procedures.
Reaction to sedation.

How long does it take to recover from a colonoscopy?

Recovery is typically quick. Most patients can return to normal activities within 24 hours. However, avoid driving, operating machinery or making important decisions on the day of the procedure due to sedation effects.

Can I go home immediately after the colonoscopy?

Yes, but you will need someone to accompany you due to lingering sedation effects.

How often should I get a colonoscopy?

Routine screening is recommended every 5 to 10 years for average-risk individuals. Dr. Aaron Poh may suggest a shorter interval based on personal or family history.

Will my insurance cover the procedure?

Most health insurance plans in Singapore cover colonoscopy, particularly when recommended for diagnostic purposes for bowel-related symptoms. However, do check with your insurer for specifics

Meet Our Doctor

DR AARON POH

Dr Aaron Poh is a fully accredited General Surgeon with dual subspecialties in Colorectal Surgery and Trauma Surgery, recognised by Singapore’s Specialist Accreditation Board and Ministry of Health. He is the Medical Director of Alpine Surgical Practice, with clinics located at Mount Elizabeth Hospital, Parkway East Hospital, and Farrer Park Hospitals.

Dr Aaron Poh has extensive experience, having performed over 5,000 endoscopic procedures. He is a strong advocate for early detection through colonoscopy, particularly for individuals at risk of colorectal cancer. His expertise includes advanced endoscopic techniques such as Endoscopic Mucosal Resection (EMR) for complex polyps and colonic stenting for obstructed cancers, which help patients avoid major emergency surgery.

When surgery is required, he specialises in minimally invasive laparoscopic colorectal cancer surgery, offering patients faster recovery with less pain and scarring. In addition to cancer care, he manages a wide range of anal conditions including haemorrhoids, fistulas, fissures, and abscesses, providing comprehensive colorectal treatment.