What Makes Colonoscopy the Gold Standard in Colon Cancer Screening?

Colonoscopy serves as both a diagnostic and preventive tool. During the procedure, doctors can identify and remove polyps, which are abnormal growths in the colon that can potentially develop into cancer. By detecting and removing them early, colonoscopy helps stop cancer before it starts. This ability to prevent cancer—rather than just detect it—is what sets colonoscopy apart from other screening tests.

While colonoscopy is widely regarded as the gold standard for colon cancer screening, several alternative methods are available, each with its own advantages and limitations.

• Faecal Immunochemical Test (FIT): This test detects hidden blood in the stool, which may indicate polyps or cancer. It is non-invasive, can be performed at home, and requires no bowel preparation. However, it must be done annually and may miss cancers or polyps that do not bleed, necessitating a follow-up colonoscopy for positive results.
• Stool DNA Test (sDNA-FIT): This test combines FIT with a test for altered DNA in the stool, which may signal cancer or precancerous conditions. Like FIT, it is non-invasive and done at home, but it is more expensive and may produce false positives, requiring further evaluation with a colonoscopy.
• CT Colonography (Virtual Colonoscopy): This method uses CT scans to create detailed images of the colon. It requires bowel preparation and involves a small amount of radiation exposure. While it can detect polyps and cancers, any abnormalities typically require a follow-up colonoscopy for removal or further evaluation, making it less definitive than a standard colonoscopy.
• Flexible Sigmoidoscopy: This procedure examines only the lower part of the colon (sigmoid colon and rectum) using a flexible tube with a camera. It requires less bowel preparation than a full colonoscopy and can often be performed without sedation. However, it misses cancers and polyps in the upper colon, so it is often used in combination with other tests like FIT for more comprehensive screening.

Colonoscopy is considered the gold standard for colon cancer screening due to several key advantages:

• Comprehensive Visualisation: Colonoscopy examines the entire colon and rectum directly in real time. This allows for detailed assessment and ensures that no section is overlooked.
• Diagnostic Precision: Colonoscopy is widely recognised for its ability to detect even small polyps or early-stage cancers that other tests may miss.
• Polyp Removal: Polyps can be removed during the same procedure, preventing potential progression to cancer without the need for additional appointments.
• Real-time Biopsy: If anything suspicious is found, tissue samples can be taken on the spot for further analysis.
• Proven Effectiveness: Colonoscopy has been used safely and effectively for decades. Its combined ability to detect and prevent cancer continues to make it the most reliable choice for many patients and clinicians.

While alternative methods like stool-based tests, CT colonography, and flexible sigmoidoscopy offer convenience and less invasiveness, they do not provide the same level of completeness or therapeutic capability. In most cases, a follow-up colonoscopy is still needed if abnormalities are found through other methods.

If you require or are considering a colonoscopy in Singapore, we encourage you to speak with our colon cancer screening specialists. Led by Dr Dennis Koh, Dr Sharon Koh Zhiling, and Dr Pauleon Tan Enjiu, our clinic provides colonoscopy screenings for proactive individuals, those at risk for colon cancer and other gastrointestinal conditions, and anyone experiencing relevant symptoms. Contact us today to schedule your appointment.