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Cancer Information

Colorectal Cancer

Colorectal Cancer

Colorectal cancer is the cancer of the colon (the main part of the large intestine) and the rectum (the passageway connecting the colon to the anus). Colorectal cancer is Singapore's top killer, affecting more than 1,865 cases each year. In most people, colorectal cancers develop slowly over several years. Before cancer forms, a growth of issue or tumour usually begins as a non-cancerous polyp on the inner lining of the colon of rectum. A polyp is a benign or non-cancerous growth which may develop into cancer over time. Not all polyps change into cancer and this largely depends on the kind of polyp.


  • Common amongst those above 50
  • Family history of colon or rectum cancer
  • Previous history of colon polyps
  • A history of ulcerative colitis (ulcers in the lining of the large intestine) or Crohn disease

*People who think they may be at risk should discuss this with their doctor.

  • Rectal bleeding or blood (either bright red or very dark) in the stool
  • A change in bowel habit
  • Persistent abdominal discomfort such as cramps or pain
  • Incomplete emptying of the bowel
  • Unexplained weight loss

*A doctor should be consulted if the symptoms above occur.

  • Practise a healthy lifestyle and maintain a healthy weight (Avoid alcohol intake)
  • Screening is advised for those above 50 years with Faecal Immunochemical Test (FIT) or colonoscopy

FIT kit

Faecal Immunochemical Test (FIT)

The FIT test checks for hidden blood in the stool, which can be an early sign of colorectal cancer. The test comes in a simple kit the size of a lighter and can easily be carried out in the comfort of your own home. The Singapore Cancer Society (SCS) (*open in new window) distributes free FIT kits to eligible Singaporeans and Permanent Residents.



A colonoscopy is a procedure that enables your doctor to examine the lining of your colon for abnormal growths. A soft and flexible tube, about the thickness of a finger, is gently inserted into the anus and advanced in. The tube has a built-in camera that allows your doctor to see your colon. The procedure usually takes about 15 to 30 minutes to complete.

Regular screening can often detect colorectal cancer early, when it is most likely to be curable. In many cases, screening can also prevent colorectal cancer as some polyps or growths can be removed before they have the chance to develop into cancer. There are several tests that examine the colon and rectum and are used to find and diagnose colorectal cancer.

Faecal Immunochemical Test (FIT)

A test to check stool for blood that can only be seen with a microscope. Small samples of stool are placed on special cards and returned to the doctor or laboratory for testing. The FIT is a quick and convenient screening test to detect early stages of colorectal cancer.

Physical Exam

Your doctor checks general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual.

Digital Rectal Exam

The doctor inserts a lubricated gloved finger into the rectum to feel for lumps or anything that seems unusual. However this detects cancer only in the last 5 to 8 centimetres of the rectum.

Barium Enema

An x-ray test using barium sulfate (a chalky liquid) to outline the inner part of the colon and rectum to look for abnormal areas on x-rays. If suspicious areas are seen, a sigmiodoscopy or colonoscopy will be needed to explore further.

Flexibile Sigmoidoscopy

This procedure examines the rectum and the sigmoid (lower) colon for polyps, abnormal areas or cancer. A flexible, thin, tube-like instrument with a light and a lens for viewing is inserted through the rectum into the sigmoid colon. 


This procedure allows examination of the whole colon for cancer. A colonoscope (a thin, tube-like instrument) is inserted through the rectum into the colon.


Depending on the stage of the colorectal cancer, there are various treatment options available. The main types of treatment that can be used for colorectal cancer include the following.


Surgery is the most common kind of treatment for all stages of colorectal cancer. There are various forms of surgery to remove the cancer including:

  • Local excision: If the cancer is found at a very early stage, the doctor may remove it without cutting through the abdominal wall. A tube will be put through the rectum into the colon to cut the cancer out. This is a local excision.
  • Resection and colostomy: If the cancer is larger, the doctor will perform a colectomy to remove the cancer and a small amount of healthy tissue surrounding it. The ends of the colon are then sewn back together. If the doctor is not able to sew the two ends of the colon back together, a stoma is made on the outside of the body for waste to pass through. This procedure is called a colostomy. A bag is placed around the stoma to collect the waste.

Radiation Therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. Radiation therapy is usually used after surgical removal of the cancer to kill any residual cancer cells around the original tumour site. It can also be used together with chemotherapy to shrink a large colorectal cancer before surgery.


Chemotherapy is the use of drugs to stop the growth of cancer. It can be administered by injecting drugs into the vein. Depending on the stage of the cancer, chemotherapy may be required after surgery to prevent recurrence and improve a person’s chance of survival. Chemotherapy may be used for patients with very advanced colorectal cancer which cannot be cured by surgery or have spread to other parts of the body.