Facts on colon cancer

Parkway Cancer Centre’s Dr Zee Ying Kiat dispels some myths about the most common cancer in Singapore.

Colorectal cancer, also known as colon or bowel cancer, is the most common cancer in Singapore. Some 1,200 new cases are diagnosed each year. It is the top cancer diagnosed in men and the second most common cancer diagnosed in women.

If it is detected early, colon cancer is also one of the most treatable and preventable forms of cancer.

Myth: If I have no symptoms, I have no colon cancer

Fact: You can be diagnosed with colon cancer even if you do not show any symptoms

In its early stages of development, colorectal cancer may not cause any symptoms. Indeed, more than half of the people diagnosed with the cancer each year had no symptoms.

As the cancer in the colorectum grows or spreads, symptoms would be more likely to occur. These vary according to the size and location of the cancer. Common symptoms include blood in the stool, changing bowel habits, persistent pain in the abdomen, bloating or cramps, feeling of bowels not emptied completely, and sudden unexplained weight loss.

 

Myth: There is no cure for colorectal cancer

Fact: Colorectal cancer can be prevented

You can prevent colorectal cancer by making dietary and lifestyle changes.

Eat more fruits and vegetables and less saturated fats and processed meats, ensure you get regular exercise, and maintain a healthy weight.

Colorectal cancer can also be prevented through appropriate screening. Regular screening for colorectal cancer is important.

Screening can not only detect colorectal cancer at an earlier stage, enabling more effective treatment, but also help to prevent the cancer from developing in the first place. It does this by finding and removing abnormal growths (polyps) in the colon or rectum before they turn cancerous.

If you are 50 years old or older, go for regular screening –  with the Faecal Immunochemical Test (FIT) to detect hidden blood in the stool once a year, and colonoscopy once every 10 years.

If you are at a higher risk of getting colorectal cancer, however, you should start screening at an earlier age and get a colonoscopy done every one to three years.

 

Myth: If I have a polyp in my colon, it means I have colorectal cancer

Fact: A polyp is a benign growth and does not mean you have cancer

Polyps, or adenomas, are benign growths. They can, however, turn into cancer over a period of time, and should, therefore,  be removed if detected early. Colorectal cancer can thus be prevented through regular screening.

A large majority of colorectal cancers arise from adenomatous polyps, gland-like growths that develop on the mucous membrane lining the large intestine. As they generally do not have any symptoms, polyps are found only through screening. One in four men will have polyps by the time he is 50 years old, and the prevalence increases with age.

It usually takes five to 10 years for a polyp to become malignant. This gives a significant period of time for colorectal cancer to be detected when it is still in a premalignant phase before a polyp becomes cancerous.

Common Screening Tests

Faecal Immunochemical Test (FIT)

A quick and convenient preliminary screening test for colorectal cancer, the Faecal Immunochemical Test (FIT) detects tiny amounts of blood in the stool. If blood is found, it needs to be followed by other tests to find the source of the blood. The FIT is easy to administer: Available in a kit, it can be done at home.

Colonoscopy

A colonoscopy involves the use of a thin, flexible tube known as a colonoscope. This is inserted through the rectum, allowing doctors to check the inner lining of the large intestine. Typically done under mild sedation, a colonoscopy takes about 15 minutes; benign polyps may be removed during the process.



Tags: cancer screening, cancerous polyps, colonoscopy, colorectal cancer, common cancer, misconceptions, prevent cancer