Every one of us is at risk for colorectal cancer. Almost 140,000 Americans will be diagnosed with colorectal cancer in 2014. The majority of people who develop colorectal cancer have no known risk factors.
Although the exact cause of colorectal cancer is not known, there are some factors that increase a person's risk of developing the disease. These include:
For the great majority of people, the major factor that increases a person's risk for colorectal cancer (CRC) is increasing age. Risk increases dramatically after age 50 years; 90% of all CRCs are diagnosed after this age. The history of CRC in a first-degree relative, especially if before the age of 55 years, roughly doubles the risk. Other risk factors are weaker than age and family history. People with inflammatory bowel disease have a much higher risk of CRC. A small percentage (<5%) of CRCs...
Age. The risk of developing colorectal cancer increases with age. The disease is most common in people over age 50, and the chance of getting colorectal cancer increases with each decade. However, colorectal cancer can develop in younger people.
Gender. The risk overall is equal, but women have a higher risk for colon cancer, while men are more likely to develop rectal cancer.
Polyps. Polyps are non-cancerous growths on the inner wall of the colon or rectum. While they are fairly common in people over age 50, one type of polyp, referred to as an adenoma, increases the risk of developing colorectal cancer. Adenomas are non-cancerous polyps that are considered precursors, or the first step toward colon and rectal cancer.
Personal history. Research shows that women who have a history of ovarian, uterine, or breast cancer have a somewhat higher risk of developing colorectal cancer. A person who already has had colorectal cancer may develop the disease a second time, especially if the first disease was diagnosed before age 60. In addition, people who have chronic inflammatory conditions of the colon, such as ulcerative colitis or Crohn's disease, are at higher risk of developing colorectal cancer.
Family history. Parents, siblings, and children of a person who has had colorectal cancer are more likely to develop colorectal cancer themselves. If two or more family members have had colorectal cancer, the risk increases to about 20%. A family history of familial adenomatous polyposis, MYH-associated polyposis, or hereditary non-polyposis colon cancer (HNPCC), increases the risk of colon cancer development. HNPCC also increases the risk for other cancers .
Diet. A diet high in fat and cholesterol and low in fiber has been linked to a greater risk of developing colorectal cancer.
Lifestyle factors. You may be at increased risk for developing colorectal cancer if you drink alcohol, smoke, don't get enough exercise, and if you are overweight.
Diabetes. People with diabetes have a 30% to 40% increased risk of developing colon cancer.
Race. The highest incidence of colorectal cancer is in African-American men and women. The incidence of colorectal cancers is lowest in Asian-Americans, Hispanics/Latinos, and American Indians and native Alaskans.
Geography: The incidence of colorectal cancer is highest in industrialized nations and lowest in Asia, Africa, and South America.
Having one or more of these risk factors does not guarantee that you will develop colorectal cancer. However, you should talk about your risk factors with your doctor. He or she may be able to suggest ways to reduce your chances of developing colorectal cancer.