What You Need To Know About Colonoscopy?

Colorectal Cancer Screening

Cancer is the #1 cause of death in Singapore, with colorectal cancer topping the list as the most common cancer affecting men, and the second most common cancer in women. In fact, it has been estimated that every day, five people in Singapore are diagnosed, two of whom die of it.

Colorectal cancer does not cause symptoms until its advanced stages when it is harder to treat, making early detection all the more crucial. For this very reason, a colonoscopy in Singapore should be done in a timely fashion in accordance to your age group and risk level.

What is a Colonoscopy?

A colonoscopy is a screening test that allows the doctor to look inside the large intestine to check for symptoms of colon cancer and other conditions affecting the organ. These include inflammatory bowel diseases that cause abdominal pain, rectal bleeding, unexplained weight loss and changes in bowel movement.

As a diagnostic tool, it can extract tissue samples from the colon for biopsies. It is also typically used as a minimally invasive manner to remove polyps, which may turn into cancer.

Furthermore, colonoscopies are done alongside other screening exams to ensure that the diagnosis is accurate. Those who have a family or medical history of colorectal conditions are advised to undergo the procedure earlier and more frequently.

How Colonoscopies Are Done

To get a clear view of the entire length of the colon, it is essential that it is purged of stools which may obstruct the doctor’s view. As such, the doctor will prescribe strong laxatives to be taken a day before the colonoscopy, to ensure that the colon is entirely cleared.

During the procedure, the patient will be asked to lie on his side with his knees bent and folded up to the chest. A colonoscope, a flexible tube with a light and camera, is then gently inserted through the anus and into the colon. The camera transmits images onto a viewing monitor, allowing the doctor to see the inside of the colon in real time.

The colonoscope is also equipped with a tube used to pump air into the colon. Though it can cause a mildly uncomfortable bloated feeling, inflating the colon gives the doctor a clearer view to check for any abnormalities.

The colonoscope is also equipped with a snare to remove abnormal tissues for biopsies and polyp removal.

The colonoscopy takes about 20 to 40 minutes and can be performed under general anesthesia. Those who choose to do the procedure without sedation may experience a bloated sensation or an urge to pass motion when the colonoscope moves or pumps air.

When & How Frequently Should A Colonoscopy Be Done?

How often a person should have a colonoscopy depends on his or her risk of developing colon cancer, and the results of previous colonoscopies, if applicable.

The recommended age to undergo a colonoscopy and other colorectal screening tests is 50 years old. Those with a low or average risk of getting colon cancer are encouraged to get a colonoscopy every 10 years after they reach the age of 50.

People who are at high risk of colorectal cancer, which include those who have a family history or previous cases of colorectal cancer or polyps, should undergo screening every 5 years once they turn 50.

If there is a history of colorectal cancer in the family, relatives are advised to get a colonoscopy around 10 years earlier than the age when the family member developed the cancer. For example, if a father was diagnosed with colon cancer at 55 years old, his children and siblings should undergo a colonoscopy at 45 years old.

Additionally, one’s lifestyle plays a role in increasing his or her risk of contracting cancer. These factors include a sedentary lifestyle with little to no physical activity, high-fat and low-fiber diet, excessive smoking and alcohol intake, and obesity.

As a general guide:

Low-risk patients: Every 10 years after the age of 50

High-risk patients: Every 5 years (for those with a family history of colorectal cancer, etc.)

  • + Possible Complications

    Colonoscopies are generally safe and well-established, but as with most medical procedures, there are some risks involved. While the possibilities are very rare in the hands of an experienced colorectal surgeon, complications include:

    • An adverse reaction to anesthesia
    • Bleeding from a biopsy or polyp removal site, though this is usually minor and self-limiting
    • Tears or perforations in the colon or rectal wall as a result of improper handling of the colonoscope in screening, biopsy or polyp removal

    However, the chance that these might happen is 0.1% or less than 1 in 1,000.

    Patients should, however, seek immediate medical attention if they experience chills, high fever, excessive rectal bleeding and severe abdominal pain after the colonoscopy.

  • + Understanding the Results of a Colonoscopy

    Normal Result:

    The result is considered normal if no abnormalities were found in the colon. However, a normal result is not a guarantee that the patient will never have colorectal cancer. Low-risk patients (no family history of colorectal cancer) are typically advised to undergo a colonoscopy once every 10 years once they are past the age of 50.

    Positive Result:

    If the initial colonoscopy results in the discovery of polyps or other abnormalities, the result is considered positive. Typically, polyps are removed on the spot during a colonoscopy and a biopsy will be taken to a lab for further testing to determine if they are cancerous or not.

    Based on the results, the doctor will discuss with the patient how often he or she should undergo follow-up screenings and further treatment, if necessary.

  • + Common Misconceptions about a Colonoscopy

    With over 2,000 searches monthly, “colonoscopy Singapore” is one of the most searched terms in the country. However, there are still many misconceptions surrounding this procedure, which include:

    • “I only need a colonoscopy when I have symptoms.” Colorecal cancer tend not to show any obvious symptoms until the disease has progressed to an advanced stage and caused irreparable damage. Colonoscopies can detect abnormalities at an early stage when they are still easily treatable. Polyps, for instance, can be detected and removed via a colonoscopy before they turn into cancer.

    • “A colonoscopy is very painful.” Colonoscopy is typically performed while the patient is sedated, so he or she will not feel any discomfort or pain. In fact, most patients will not have a recollection of the entire procedure.

    • “The procedure might damage my colon.” The screening test can only be performed by a doctor who is trained in colonoscopy, hence greatly reducing risks of complications. With a properly trained professional, the risk of bleeding is less than 1% and the probability of colon perforation is 1:1000.

    • “Men are more likely to get colon cancer.” On the contrary, colorectal cancer is the #1 cancer in Singaporean men, and the #2 cancer in Singaporean women.
  • + Are There Alternatives to a Colonoscopy?

    The fear of colonoscopies often arises from a misconception that the procedure is a painful ordeal. However, with the use of sedatives and in the hands of a reputable and skilled surgeon, colonoscopy is a quick, painless and very accurate diagnostic method. However, alternatives to examine the colon do exist, and they include:

    Barium Enema:

    Also known as colon X-ray, a barium enema is designed to look for abnormalities in the large intestine. This procedure funnels a harmless, white liquid (barium) into the colon through the anus via a tube (enema). The barium coats the colon to produce a clear silhouette that can be captured on X-ray. Air may be pumped in to expand the colon and enhance the quality of the X-ray image. This method is performed without sedatives.

    CT Colonography:

    This method, also called virtual colonoscopy, uses both X-rays and CT scanners to create two- to three-dimensional images of the large intestine. Before the patient enters the CT scanner, air will first be pumped into the colon via a tube inserted through the anus. Similar to a barium enema, the doctor will produce images with the patient in varying positions.

    Both methods will require the clearing of the colon/bowels beforehand, and are done without sedatives. Furthermore, if the results of barium enema and CT colonography come out positive with signs of polyps and other abnormalities, a colonoscopy will still need to be done for biopsy and removal. Therefore, a colonoscopy is still the most recommended and worthwhile method.


    Dr. Ho Kok Sun is a well-established colorectal surgeon in Singapore specializing in the diagnosis and treatment of colorectal cancer. His interest lies in the field of advanced therapeutic endoscopy and colonoscopy, and laparoscopic colorectal surgery. Dr. Ho is also one of only few surgeons certified to perform robot-assisted surgery. Contact us today at 6737 2778 for a detailed consultation.

Because No Symptom Is Ever Too Late Early Detection Helps Saves Lives

FOR MORE INFORMATION, CALL US AT (+65) 6737 2778

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