Advanced Notice – Colonoscopy Screening: Is It Still Necessary?

By Dr Chew Min Hoe

The Debate Over Colonoscopy Screening

The relevance of colorectal cancer (CRC) screening came under scrutiny when a large international study questioned whether colonoscopy effectively prevents deaths from the disease. The study’s results led to confusion among the public after major media outlets highlighted its limitations without explaining the context. Many healthcare professionals — including those in Singapore — quickly pointed out flaws in the study’s design and interpretation.

Understanding the NordICC Trial

The Nord-European Initiative on Colorectal Cancer (NordICC) trial, published in the New England Journal of Medicine on 10 October 2022, involved 84,585 participants aged 55 to 64 from Poland, Sweden, the Netherlands, and Norway. These individuals had never undergone CRC screening. Researchers divided them into two groups — one invited for colonoscopy screening and one not invited — and followed them for ten years (2009 – 2014).

Key outcomes were:

CRC risk reduction: 18% lower in the invited group.
CRC-related death: 0.28% in the invited group versus 0.31% in the control group.
All-cause mortality: Similar at about 11% in both groups.
Number needed to invite: 455 invitations to prevent one CRC case.

Why the Results Sparked Debate

Experts raised several concerns about the trial’s design and interpretation:

Low Participation: Only 42% of those invited actually underwent screening. Because more than half declined, the data underestimated colonoscopy’s true benefit.
Variable Quality: Nearly one-third of endoscopists did not meet the recommended adenoma detection rate of 25%. Missed polyps could have progressed to cancer.
Statistical Approach: The “intention-to-treat” analysis grouped everyone invited to screening — even those who refused — as if they had been screened. When researchers re-analysed only those who underwent colonoscopy, they found a 31% reduction in CRC risk and a 50% lower CRC-related death rate.

Lessons for Singapore’s Population

Although Singapore’s healthcare system is among the world’s best — with highly trained professionals, modern hospitals, and strong research capabilities — CRC remains one of the most common and deadly cancers locally.

According to the Singapore Cancer Registry 2019, over 57% of CRC cases are still diagnosed at advanced stages III or IV. Unlike some other cancers that are increasingly detected early, CRC diagnosis patterns have barely improved in the past two decades.

Encouraging More People to Get Screened

Low screening uptake remains a major obstacle. Annual Fecal Occult Blood Test (FOBT) campaigns are available, but participation rates are poor. To improve awareness and screening adoption, several developments have emerged:

1. Colonoscopy Technology Has Improved

Newer colonoscopes use Artificial Intelligence (AI) and narrow-band imaging, allowing specialists to detect smaller or hidden polyps more effectively.

2. Better Training and Public Access

Structured training programmes in public hospitals ensure consistent quality across surgeons and gastroenterologists. Both public and private healthcare now provide access to skilled endoscopists.

3. Support from Insurers and Public Education

Some insurance packages include free screening — a positive step that recognises the long-term cost savings of prevention. Public forums, community talks, and awareness drives also encourage individuals to go for early screening as part of the national “Healthier SG” preventive-care movement.

New CRC Screening Tools

For those hesitant about colonoscopy, non-invasive alternatives like the Epi proColon PCR blood test are emerging. This test detects methylated Septin 9 DNA, a biomarker released by colon and rectal cancer cells — even in early stages.

Accuracy: 81% sensitivity and 99% specificity in asymptomatic individuals.
Result: Reported as “low risk” or “high risk.”
Next steps: A high-risk result warrants a diagnostic colonoscopy, while a low-risk result should be monitored with a repeat test after one year.

These tests do not replace colonoscopy but provide an option for those unable or unwilling to undergo the procedure.

Colonoscopy Screening: Still Relevant and Necessary

Despite the recent debate, CRC screening remains vital. The NordICC trial highlights the importance of interpreting research accurately rather than abandoning proven preventive measures.

In Singapore, early detection can save lives. Coordinated efforts between policymakers, healthcare professionals, insurers, and communities are key to reducing CRC incidence and mortality. While colonoscopy remains the gold standard, new tools such as blood-based tests can complement it by reaching individuals who might otherwise avoid screening.

The Bottom Line

Colonoscopy screening continues to be one of the most effective ways to detect and prevent colorectal cancer. With better awareness, improved technology, and accessible alternatives, more people can take charge of their health — helping Singapore move closer to a future where fewer lives are lost to CRC. PRIME

Author

Dr. Chew Min Hoe

Medical Director & Senior Consultant, General & Colorectal Surgeon

The Surgeons
MBBS, MRCS (Edinburgh), MMed (Surgery), FRCS (Edinburgh)

Dr Chew Min Hoe graduated from NUS in 2001. He subsequently obtained his Master of Medicine in Surgery from NUS in 2006 and became a Fellow of the Royal College of Surgeons of Edinburgh in 2010.

Dr Chew was awarded the Singhealth Human Manpower Development Plan (HMDP) Award to pursue further training in complex pelvic surgery, and completed his Fellowship at the Royal Prince Alfred Hospital (Sydney, Australia) in 2011-2012. His clinical specialty is General and Colorectal Surgery with special niche interests in colorectal cancer, difficult locally advanced pelvic cancers, genetic hereditary colorectal conditions as well as perianal surgery.

Dr Chew is highly involved in education and research, and has published more than 100 peer-reviewed articles.

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