Colorectal Cancer: A Common Sense Approach

07 Mar 2018

It’s the most common cancer in Singapore, and your risk of getting it increases with age. Dr Mark Wong, General and Colorectal Surgeon from Mark Wong Surgery, prescribes a common sense approach to prevention and treatment.


Colorectal cancer refers to a malignant tumour that starts as a polyp, or small growth, along the inner wall of the colon and rectum. Warning signs include a change in bowel habits, such as persistent or alternating pattern of diarrhoea or constipation, a change in the frequency of stools, and the presence of blood in stools.

Since polyps generally take years, not weeks or months, to become cancerous, regular screening can intercept their development by simply removing them before they become cancerous.

While not all polyps become cancerous, it is not possible to tell which ones will and which ones won’t, according to Dr Mark Wong. Therefore, all polyps are routinely removed during screening.


Modifiable risk factors for colorectal cancer include obesity, physical inactivity and smoking. And it does affect younger patients as well. In the younger patient, it may be related to genetically-linked hereditary cancer syndromes, which place immediate family members of sufferers at higher risk of developing it during their lifetime.

For reasons not fully understood, colorectal cancer affects more men than women. In fact, it is the most common cancer among Singaporean men, and the second most common cancer among Singaporean women. The latest report from the National Registry of Diseases Office (NRDO) revealed that more than 9,800 new cases in total were diagnosed between 2011 and 2015.

The same report states that the specific incidence rate of colorectal cancer rose steeply past the age of 50 years, regardless of gender, with more than three in four colorectal cancer patients diagnosed above the age of 55. The peak incidence was noted in the 55 to 64 years age group in males, and after 75 years in females.


An annual Faecal Immunochemical Test (FIT) is generally recommended from the age of 50 onwards. For those with a family history of the disease, Dr Wong recommends commencing screening 10 years before the age of diagnosis for the youngest colorectal cancer sufferer in the family. FIT is non-invasive and free for all Singaporean citizens and Permanent Residents above the age of 50 years, and can be carried out in the comfort of your own home. It involves collecting a stool sample, which is sent to a laboratory for testing.

If the FIT result is positive, patients will normally undergo a colonoscopy to rule out or confirm the presence of colorectal cancer.

“Colonoscopy is regarded as the ‘Gold Standard’ for colorectal cancer screening as it is the most accurate and reliable method available,” shared Dr Wong.

Using, high-definition, fibre-optic technology, a colonoscopy allows the doctor performing the procedure to view the inner wall of the colon and rectum in detail. If any polyps or cancers are identified, they can be biopsied or removed immediately.

An alternative method of screening is a CT scan for the colon and rectum, known as CT colonography. Unlike a colonoscopy, it does not allow removal or biopsy of suspicious findings.


Keyhole or minimally-invasive surgery is regarded as standard of care by many colorectal surgeons. Chemotherapy and radiotherapy are generally reserved for more advanced cancers that have spread beyond the colon and rectum.

In the first few months after surgery, patients are advised to avoid strenuous exercise and lower their intake of dietary fibre to reduce bloating and constipation. Patients may also experience more liquid and frequent stools, but this usually abates over time.

Some patients, particularly the elderly and those with rectal cancers, may experience some faecal incontinence or involuntary leakage of stool after surgery, especially if treatment involves radiotherapy. This can generally be improved with medications and pelvic floor exercises.


Under no circumstances does Dr Wong recommend detox programmes or colon hydrotherapy. He explained,“A healthy colon needs a flora of bacteria, which requires having faeces in the colon. Think of a luxuriant rainforest with its vibrant ecosystem of animals and plants as a normal colon with faeces. Compare this to a scorched forest after a raging fire – this is a colon washed clean of faeces by detox or hydrotherapy.”

Instead, Dr Wong advocates a balanced approach to preventing colorectal cancer. He recommends a healthy diet, incorporating all food groups in moderation, with regular exercise and most importantly, regular screening.

In Singapore, the five-year survival rate for people with Stage 1 colorectal cancer is between 85 to 95 percent. On the other hand, the survival rate for people with Stage 4 is less than five percent. Though prevention is always better than cure, with early detection, the future can still look bright for people diagnosed with colorectal cancer.

Article contributed by Dr Mark Wong Te Ching, an accredited doctor of Mount Alvernia Hospital.

This short take is taken from our My Alvernia Magazine Issue #33. Click here to read the issue on our website or on Magzter.