Colorectal cancer

Colorectal cancer is the second most common cancer in Peninsular Malaysia, the first among male and second among female. Worldwide, the incidence of colorectal cancer is increasing and it is still one of the leading health problems.

The exact cause of colorectal cancer is unknown, although some are hereditary in origin(inherited). However, it is widely accepted that it originates from the progression of some non-cancerous growth called adenomatous polyp which later on become cancerous over a period of a few years. Therefore, early detection and removal of these polyps can potentially prevent the development of colorectal cancer.

Some of the common symptoms of colorectal cancer are changed in bowel habit, sensation of incomplete bowel motion, weight loss and passing blood in the stools. However, one should not have a misconception that passing blood in stools is only due to piles because piles, being so common, can coexist with other more serious conditions like cancers, inflammatory bowel disease and ischemic bowel which require further assessment and investigations.

The benefit of screening for colorectal cancer is very strong and clear as it fulfills many criteria of a good screening i.e. colorectal cancer is one of the commonest cancers, it potentially improves the outcome of the disease if colorectal cancers are detected earlier, it is highly sensitive and the screening modalities are generally acceptable.

There are several ways of screening for colorectal cancers. These include stool occult blood tests, radio-imaging (x-rays) and colonoscopy. However, colonoscopy remains to be the final common pathway for all positive screening tests, i.e. if the screening test by a method other than colonoscopy turns out to be positive, the patient would be advised for colonoscopy and biopsy for confirmation of diagnosis. Colonoscopy detects and also removes adenomatous polyps at the same time and potentially stops the progression of polyps into cancers.

Once a diagnosis of colorectal cancer is made, the disease is usually further investigated for staging of the cancer. The mainstay of treatment is surgery and it may be combined with chemotherapy and radiotherapy depends on the stage and site of the colorectal cancer.

The good news about colorectal cancer is that it is potentially curable if detected early and potentially preventable if the adenomatous polyps are removed.