Colorectal cancer is the second most commonest cancer in Malaysia. It can affect any part of the colons and rectum. Left- sided colon cancer is the commonest form. Colorectal cancer may not cause symptoms in the early stage. Most colorectal cancer arise from polyps that progress in size gradually and later to cancer. The slow transition of polyps to cancer provide window of opportunity for screening and early detection.
Colorectal cancer symptoms including new change of bowel habits such as new diarrhea or constipation, pain when passing motion, sensation of incomplete bowel movement, fresh blood or mucus in the stool, change in the color of the stool (black color), mass in the abdomen, pain or distension in the abdomen, feeling tired, low appetite, weight loss and presence of anaemia in the blood testing. For patient with symptoms, urgent referral to colonoscopy is needed.
Colorectal cancer screening should be offered regularly to average risk patients defined as having no symptoms, no family history of colorectal cancer and age of 50 years and above. The preferred method of screening is using faecal occult blood test (FOBT). If the result is positive, colonoscopy is indicated and if the result is negative, yearly test should be performed until the age of 75 years old.
In high risk group of patient for example with family history of colon cancer (diagnosed at aged of less than 60 years old), colonoscopy should be performed at aged of 40 or 10 years younger than the affected relatives (whichever is younger). If normal, for repeat of colonoscopy every 3–5 years and stop screening at age of 75 years. Referral to colorectal specialist is indicated to decide on risks and screening frequency for patient with hereditary colorectal cancer syndromes and inflammatory bowel disease.
Colonoscopy enables visual inspection of the large colon, biopsy and removal of the polyp. Prior to colonoscopy, your doctor will prescribe medication to help clear all the faeces in your colon to provide better visualization of the colon wall during the procedure. Patient will usually be sedated and placed on the left side of the body. During colonoscopy, a scope which is a long flexible tubing instrument with camera at the front end will be inserted from the anus. Any abnormal tissue will be removed and send to the lab to check for cancerous changes. Colonoscopy is a relatively safe procedure with low incidence of bleeding and perforation.
If you have any further question or would like to do colorectal cancer screening, talk to our doctor.