Screening and prevention of colorectal cancer

Colorectal cancer is over 90% preventable through screening, healthy eating, and exercise.

Because most cases of colorectal cancer begin with the development of benign or non-cancerous polyps that can become cancerous, regular screening is critical to find and remove polyps in the early stages.

The Colorectal Cancer Association of Canada (CCAC) recommends that all Canadians be screened starting at age 50, while those with a family history of the disease should be screened earlier.

Current methods of colorectal cancer screening include:

• fecal occult blood test (FOBT), which checks for blood in the stool - a possible indication of pre-cancerous polyps
• barium enema, a test that consists of introducing a liquid containing barium into the colon and then taking X-rays to help detect polyps or tumours (see Figure 2)
• flexible sigmoidoscopy, a test in which a soft, flexible lighted tube is used to look at the lining of the rectum and lower colon to help detect or rule out the presence of polyps or tumours (see Figure 3)
• colonoscopy, which uses a thin, flexible tube with a camera at its tip; it is like the flexible sigmoidoscope but longer. Colonoscopy, which is known as the gold standard for screening, allows a physician to view the entire colon - and remove any polyps that are found, thus preventing colorectal cancer from developing (see Figure 3).

Figure 2

Barium enema

Figure 3

Colonoscopy and sigmoidoscopy

Figure 4

Colon biopsy