Colorectal Cancer Screening and Prevention

Colorectal cancer is the third most common cancer in Canada and is the second most common cause of death from cancer among both men and women. If detected early colorectal cancer is highly treatable and may not be so deadly.

What is Colorectal Cancer?

Colorectal cancer usually begins as a polyp, which is an unwanted growth that occurs in the large bowel. Polyps are relatively common in people over the age of 50 and most are benign.

However, polyps known as adenomas are believed to be precursors of most colorectal cancers. Precancerous and early-stage colorectal cancers do not always cause symptoms.

If symptomatic, they may present with blood in or on your stool, black or dark coloured stools, stomach pains that do not resolve, unintentional weight loss, fatigue, changes in bowel habits, narrowing of stools, and/or iron deficiency anemia.

Who is at Risk?

Though colorectal cancers can occur at any age, 90% of cases appear in people over the age of 50.

Many of these individuals do not have a family history of colorectal cancer. However, some women with a history of ovarian, uterine, and/or breast cancer have a higher than average chance of developing colorectal cancer.

Family history of colorectal cancer in a first degree relative prior to the age of 60 or two second degree relatives prior to the age of 60 can also indicate an increased risk. Individuals with inflammatory bowel disease for 8 years or more (such as ulcerative colitis and Crohn’s disease) are also at greater risk.

Lifestyle Choices Can Increase Risk

There is some evidence to suggest that diets high in

  • red meat and processed meats,
  • high in fat, and
  • low in whole grains, fruits and vegetables

may be associated with the development of colorectal cancer.

There is also evidence to suggest that a sedentary lifestyle and obesity may be associated with increased risk of developing colorectal cancer. Alcohol consumption (especially beer) and cigarette smoking can also increase the risk of colorectal cancer.

Regular Colorectal Cancer Screenings start at 50

Screening refers to the detection of disease before symptoms appear. Statistics show that if everyone age 50 and over had regular screenings, at least 60% of deaths from colorectal cancer could be avoided.

Some screening tests not only detect cancer at an early stage but can actually go one step further by preventing colorectal cancers altogether when precancerous polyps are detected and then surgically removed.

If you are age 50 or older, having a colorectal cancer screening test can save your life. Please speak to your family doctor about the various screening modalities available and the pros and cons of each.

Family history of Colorectal cancer? Start screening at 40

If you have a family history of colorectal cancer in a first degree relative or two second degree relatives that occurred before the age of 60, you should be screened at the age of 40, or 10 years before your relatives’ diagnosis (whichever is sooner).

Lifestyle Modifications for Colorectal Cancer Prevention

Lifestyle modification through:

  • smoking cessation,
  • stress reduction,
  • improved diet (reduced meat, fat, and alcohol consumption, and higher fiber, fruit, vegetable consumption) and
  • higher levels of physical activity

will offer you the best opportunity to reduce your risk of colorectal cancer.

About the author: Dr. Olivia Kei is a family physician at the Copeman Healthcare Centre in Vancouver. Prior to joining us, Dr. Kei operated a full-time family practice in Toronto in addition to working as a walk-in physician and an investigator for a clinical research facility.

Dr. Kei completed her postgraduate medical education at the University of Toronto’s Department of Family and Community Medicine.