Dr C.K. Leow
Liver, Pancreas, Colon and General Surgery

Colorectal Cancer and You

Colorectal cancer is the second most common cancer in Singapore for both men and women. Forty years ago, colorectal cancer was ‘rare’ in Singapore. Now, the incidence is no different from that in the West. When colorectal cancer is discovered early, there is a good chance of being cured.


  1. Change in bowel habit — Your normal habit of going to the toilet has changed. You could either be going to the toilet more often than normal or going less often. The consistency of the motion has become loose and slimy.
  2. Passing blood in stool — The passage of blood during defaecation can be confusing as haemorrhoids can cause bleeding too. Bleeding due to colorectal cancer can be fresh, semi-fresh or altered blood. It may not occur every time you go to the toilet.
  3. The stool is thinner — This can occur if the lumen of your colon is narrowed by the cancer. In some patients, this is also associated with the need to push harder when defaecating.
  4. Unexplained weight loss and tiredness — These symptoms are not very specific and you may not be able to pinpoint the reasons why.
  5. Bloated feeling and abdominal pain — You may complain of bloatedness and your abdomen feels larger than normal. In some, crampy abdominal pain may be a regular complaint.


After a complete physical examination, the definite diagnosis is normally obtained by performing a colonoscopy (a long flexible telescope). The colonoscope is passed through the anus and the entire colon is examined under intravenous sedation. A small piece of the colon cancer is removed during the colon examination. The result of the microscopic examination of the tissue is to confirm the diagnosis of colorectal cancer.

Colorectal cancer can also be diagnosed by performing an X-ray examination called double contrast barium enema. This is not as invasive and costs less to perform. However this examination can miss small cancers and it is not possible to remove a small piece of the cancer for confirmation.


The main stay treatment for colorectal cancer is surgery. The aim of the operation is to remove all visible cancer in the colon. Subsequently, some patients will need to undergo a period of chemotherapy. This treatment is delivered by the medical oncologist. In some patients, radiation therapy may also be necessary.

In patients with rectal cancer, sometimes it may be necessary to treat the cancer with radiation therapy and chemotherapy before the surgery is performed.


Someone with an underlying colorectal cancer tends to have symptoms for a period of time. When you are made aware of the tell tale signs of a colorectal cancer, you can be on the look out. Hopefully this will lead to an earlier diagnosis of the condition with a chance to cure. Colorectal cancer can spread to the liver. Nowadays the outlook for some of these patients has certainly been improved by combining aggressive liver surgery with chemotherapy. This approach of combining liver surgery and chemotherapy has certainly given them a chance to cure.