14.MAR.2018 5 MIN READ | 5 MIN READ

Colorectal cancer is mostly a slow-growing disease and highly curable if caught early in a health screening. We speak to Dr Mark Wong to get the facts.

When should I get screened for colorectal cancer?

When you hit the big 50 or you’ve never been screened before, now is the time to take a Faecal Immunochemcial Test (FIT). The National Registry of Diseases Office (NRDO), under the auspices of the Ministry of Health, reports that the estimated lifetime risk for developing cancer in the Singapore population is approximately 1 for every 4 – 5 people. 

Based on the report from NRDO, cancer rates rose steeply after the age of 50, regardless of gender. Based on this, it makes sense to take the feacal test from 50 years old onwards. Furthermore, it is non-invasive, free for all Singaporean citizens and PRs above 50, and serves as a convenient first-step to screening. If the result is positive, patients should then seek medical advice for a more thorough check.

Besides FIT, are there other screening methods?

Other screening methods
Colonoscopy is regarded as the gold standard for colorectal cancer screening as it is the most accurate and reliable method available. Using high definition, fibre-optic technology, a flexible tube inserted into the anus allows the doctor performing the procedure to view the inner wall of the colon and rectum in detail, so that any polyps or cancers can be identified, biopsied and removed.

Another alternative is a CT scan for the colon and rectum (CT colonography). However it does not allow removal or biopsy of suspicious findings, something that requires a colonoscopy.

What causes colorectal cancer?

Colorectal cancers start as polyps, or small growths along the inner wall of the colon and rectum. Not all polyps develop into cancer, but we cannot tell which will, therefore we remove all polyps seen during screening. Since polyps take years to become cancerous, if at all, we have the lead time to stop the process and prevent cancer, if patients come for screening that is.

Am I at risk, and what can I do about it?

Colorectal cancer symptoms
There are many factors involved – some you can take action to reduce your risk, some you can't do anything about.

Those that you can take action to change include lifestyle and behavioural factors such as obesity, physical inactivity and smoking.

Those that you can't change are genetic or hereditary factors, such as family members with colorectal polyps and colorectal cancer. 

I’m under 50. So I’m not at risk, right? 

Yes, you still could be, especially if your family has a history of hereditary cancer syndromes, where patients and their family members are more prone to developing multiple cancers in their lifetime. Most commonly known syndromes are Familial Adenomatous Polyposis (FAP) and Hereditary Non Polyposis Colorectal Cancer (HNPCC).

Demographically, it is the no. 1 killer for men. Why? 

Men at higher risk
No one really knows why more men than women develop colorectal cancers. However, it is also the second most common cancer in women, and the most common cancer in Singapore in all, with more than 9,800 new cases diagnosed from 2011 to 2015.

What are the available treatments for colorectal cancer?

The most effective treatment is still surgery. Nowadays, keyhole or minimally-invasive surgery is regarded as the standard of care by many colorectal surgeons. This allows us to remove the colorectal cancer safely and effectively through smaller incisions, resulting in smaller wounds, less pain and a quicker recovery for patients.

Other treatments include chemotherapy and radiotherapy, but this is generally reserved for only more advanced cancers that have spread beyond the colon and rectum.

What would I expect post-op?

Post-operation expectations
As with any major surgery, patients are advised to avoid strenuous exercise for up to 3 months after surgery. In addition, they are also advised to take less dietary fibre in the initial months after surgery to reduce bloating and constipation. But in the long term, there are no significant changes required.

Patients can, however, experience changes in their bowel habits. As the main function of the colon is to absorb fluids to make stools form, the removal of part of the colon often results in more liquid and frequent stools, but this usually settles with time. 

With surgery involving removal of part of or the entire rectum, especially with the addition of chemotherapy and radiotherapy, many patients face challenging issues of faecal incontinence, particularly in the elderly. But this can be dealt with using medications and pelvic floor exercises.

Does colon cleansing supplements, a detox, or having colon hydrotherapy help prevent colon cancer?

No. A healthy colon needs its unique flora of bacteria within to make it healthy. This requires having faeces in the colon. 

I draw a parallel to a luxuriant rainforest with its vibrant ecosystem of animals and plants as a normal colon with faeces. Compare this to the scorched forest after a wildfire being a colon washed clean of faeces by detox or hydrotherapy… the answer is obvious!

Do you have tips and advice to prevent colorectal cancer?

Prevention tips and advice
Colorectal cancer is preventable since it starts as polyps and take years to become cancerous, if at all. We can remove polyps to stop them from becoming cancerous. Colorectal cancer is also very treatable in the early stages. Unfortunately, we are still diagnosing the disease at advanced stages due to public ignorance and fear of screening.

BIGGEST TIP!

Stay healthy by eating all food groups in moderation and exercising regularly.

Come for colorectal cancer screening at 50 years or 10 years before the age of the youngest colorectal cancer patient in your family (whichever is earlier). Do not ignore symptoms like blood in the faeces, loss of weight or appetite, and changes in bowel habit.

14.MAR.2018
img
Wong Te Ching Mark
General Surgeon
Mount Elizabeth Hospital

Dr Mark Wong is a general surgeon practising at Mount Elizabeth Novena Hospital and Parkway East Hospital, Singapore. His special interests are in minimally invasive (laparoscopic) and robotic surgery for both cancer and benign bowel disorders.