The Role of Colonoscopy in Colorectal Cancer Detection
Colorectal cancer is one of the more commonly diagnosed cancers among adults in Singapore. As symptoms may not appear during the early stages, screening and timely medical evaluation play an important role in identifying abnormalities within the colon and rectum. Among the available screening and diagnostic methods, colonoscopy is commonly used to examine the large intestine and investigate potential colorectal conditions.
A colonoscopy may be recommended for routine screening, follow-up after abnormal stool test results, or assessment of digestive symptoms. It also allows doctors to identify and remove certain polyps that may develop within the colon over time.
What Is Colorectal Cancer?
A colonoscopy is a procedure used to examine the inside of the colon and rectum using a flexible tube fitted with a small camera. The instrument is gently inserted through the rectum, allowing the doctor to assess the lining of the large intestine for abnormalities.
During the examination, doctors may look for:
- Polyps
- Inflammation
- Areas of bleeding
- Tissue abnormalities
- Signs associated with colorectal cancer
If necessary, small tissue samples may also be collected for laboratory testing. Certain polyps can also be removed during the procedure for further evaluation.
Why Colonoscopy Plays a Role in Colorectal Cancer Detection
Colonoscopy is widely used because it allows direct visual examination of the colon and rectum. In some cases, colorectal cancer develops from polyps that gradually change over several years. Identifying these growths early may support timely medical management.
One of the key advantages of colonoscopy is the ability to detect abnormalities even before symptoms appear. Some individuals with colorectal cancer or polyps may not notice any warning signs during the early stages.
Colonoscopy is also commonly performed following a positive Faecal Immunochemical Test (FIT), which checks for traces of blood in stool samples. A positive FIT result does not automatically indicate cancer, but additional assessment is often required to determine the cause.
Who May Be Recommended for a Colonoscopy?
Adults Undergoing Routine Screening
Adults aged 50 years and above are commonly encouraged to discuss colorectal cancer screening with their doctor, even if they feel well and do not have symptoms. Colonoscopy may be recommended at intervals based on individual health factors and previous findings.
Individuals Experiencing Symptoms
A colonoscopy may also be advised for individuals experiencing symptoms such as:
- Blood in stools
- Ongoing constipation or diarrhoea
- Persistent changes in bowel habits
- Abdominal discomfort
- Unexplained weight loss
- Fatigue linked to anaemia
These symptoms may be associated with various digestive conditions and should be assessed by a healthcare professional where appropriate.
Individuals With Higher Risk Factors
Some people may require earlier or more regular screening due to increased risk factors. These may include:
- Family history of colorectal cancer
- Personal history of colorectal polyps
- Inflammatory bowel disease
- Certain inherited conditions linked to colorectal cancer
Screening recommendations can vary depending on personal and family medical history.
How to Prepare for a Colonoscopy
Dietary Preparation
Before the procedure, patients are usually advised to make temporary dietary changes. This may involve avoiding high-fibre foods and consuming lighter meals in the days leading up to the colonoscopy.
Bowel Preparation
Patients are typically prescribed bowel-cleansing medication before the procedure. Clearing the bowel helps improve visibility during the examination and supports a more thorough assessment of the colon lining.
Following preparation instructions carefully is important, as incomplete bowel preparation may affect the examination.
Medication Considerations
Patients should inform their doctor about any medications they are taking, including blood-thinning medication, diabetes medication, or supplements. Adjustments may sometimes be required before the procedure.
What Happens During a Colonoscopy?
On the day of the procedure, patients are generally given sedation to help them remain comfortable during the examination. Once prepared, the colonoscope is inserted through the rectum and guided through the colon.
The procedure typically takes between 20 and 45 minutes, depending on the findings and whether additional procedures are carried out.
During the colonoscopy, the doctor may:
- Examine the lining of the colon and rectum
- Remove polyps
- Collect biopsy samples
- Assess abnormal areas for further investigation
Most patients do not remember much of the procedure due to the effects of sedation.
What Happens During a Colonoscopy?
After the procedure, patients are monitored while the sedation wears off. Some individuals may experience mild bloating or temporary discomfort due to air introduced during the examination.
Doctors may provide an initial explanation of the findings after the procedure. However, if tissue samples or polyps are sent for laboratory analysis, the final results may take several days.
Depending on the outcome, follow-up appointments or additional investigations may sometimes be recommended.
Possible Risks and Limitations of Colonoscopy
As with most medical procedures, colonoscopy carries some potential risks. These may include:
- Temporary bloating or abdominal discomfort
- Mild bleeding after removal of polyps
- Reactions related to sedation
- Rare complications such as bowel perforation
Patients are usually advised to discuss the potential benefits and risks with their healthcare provider before proceeding with the examination.
Colonoscopy and Colorectal Cancer Prevention
Colonoscopy may contribute to colorectal cancer prevention through the identification and removal of certain polyps before they develop further. Regular screening also supports earlier detection of abnormalities that may require medical attention.
For individuals with higher risk factors, ongoing surveillance and follow-up examinations may form part of long-term colorectal health monitoring.
Accessing Colonoscopy Services in Singapore
Individuals may be referred for evaluation through general practitioners, polyclinics, gastroenterologists, or colorectal doctors.
Screening eligibility and recommendations may differ based on age, symptoms, family history, and overall risk profile.
Lifestyle Habits That May Support Colorectal Health
In addition to screening, certain lifestyle habits may support colorectal health, including:
- Maintaining a balanced diet with sufficient fibre
- Staying physically active
- Limiting alcohol intake
- Avoiding smoking
- Attending regular health check-ups
Individuals with concerns about digestive symptoms or screening suitability may consider discussing these matters with a healthcare professional.
Colonoscopy plays an important role in the detection and evaluation of colorectal abnormalities, including polyps and colorectal cancer. Because early-stage colorectal cancer may develop without noticeable symptoms, screening discussions are important for adults, particularly those aged 50 years and above or individuals with increased risk factors.
Speaking with a colorectal doctor may help individuals better understand suitable screening options based on their personal health needs and medical history.
