Colorectal cancer is cancer of the colon and/or rectum. In most cases, colon and rectum cancers develop slowly over a period of several years. Most of these cancers begin as a polyp—a growth of tissue into the center of the colon or rectum. With colorectal cancer screening, polyps can be found and removed before they turn into cancer, and colorectal cancer can be found earlier when it is easier to cure.
While the disease can strike at any age, about 90% of people affected by the disease are over age 50. The risk factors include:
- Ethnicity: African Americans have a greater risk of colon cancer than other ethnicities
- History: Patients who have had colon cancer or adenomatous polyps have a greater risk of future colon cancer and those with a parent, sibling or child who has had colon cancer or rectal cancer have a greater risk of colon cancer
- Chronic inflammatory diseases of the colon: Those with inflammatory intestinal conditions, including ulcerative colitis and Crohn’s disease, have an increased risk of colon cancer
- Genetics: Genetic syndromes increasing the risk of colon cancer include familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer (Lynch syndrome)
- Diet & Lifestyle: Colon and rectal cancer may be associated with a high-fat, low fiber diet, a sedentary lifestyle, smoking and heavy use of alcohol
- Diabetes: Patients with diabetes and insulin resistance may be more likely to develop colon cancer
- Obesity: Those who are obese have an increased risk of developing and dying from colon cancer compared to those of normal weight
- History of radiation therapy: Patients who have undergone radiation therapy directed at the abdomen may have an increased risk of colon cancer.
Despite the lifesaving potential of colorectal screening, only a fraction of people who should be screened actually get the tests they need.