Age

Age increases the risk for developing colorectal cancer. Approximately 90% of people who get colorectal cancer are over the age of 50. Early onset colorectal cancer (diagnosed before the age of 45 years) is increasing in the United States, with a larger proportion of new diagnoses of colorectal cancer occurring every year in this setting .

Family History

Close relatives of a person who has had colorectal cancer are more likely to develop the disease.

Colorectal Polyps

People with polyps in their colon are more likely to get colorectal cancer.

Genetics

About 5% to 10% of all cases of colorectal cancer are caused by inherited genetic mutations such as hereditary non-polyposis colon cancer (HNPCC) and familial adenomatous polyposis (FAP).

• Hereditary non-polyposis colon cancer (HNPCC): HNPCC is the most common form of inherited colon cancer and accounts for about 3% to 5% of all colorectal cancers. This disease is caused by mutations in the HNPCC (MSI) gene. People with these mutations have about an 80% chance of developing colorectal cancer in their lifetimes and women with HNPCC are at a higher risk for developing uterine cancer.
• Familial adenomatous polyposis (FAP): FAP is a rare condition that can cause thousands of polyps to form in the colon or rectum. It is caused by a mutation in the APC gene. FAP usually leads to colorectal cancer by age 40. If left untreated, it may even turn into cancer as early as age 20.

Inflammatory Bowel Disease

Inflammatory bowel diseases such as Ulcerative colitis and Crohn’s disease cause pain and swelling in the colon and increase risk for colorectal cancer.

Ethnicity

African Americans and Jews of Eastern European descent are at higher risk for developing colorectal cancer.

• Jews of Eastern European descent may have an inherited genetic mutation called APC I1307K, which increases the risk.
• African Americans have the highest incidence and mortality rates of any ethnic group. However, these cases are not linked to any specific genetic changes, and the reasons for this increased risk are unclear.

Type 2 Diabetes

People with type 2 diabetes are more likely to develop colorectal cancer.

Diet

A diet high in fat and red meats, and/or low in fiber, can increase your risk for colorectal cancer.

Obesity

Being very overweight, especially with too much fat in the stomach region, may increase your risk of getting colorectal cancer.

Alcohol

Heavy alcohol consumption is associated with an increased risk of developing colorectal cancer.

Tobacco

Smokers are about 30% to 40% more likely to develop colon polyps than non-smokers are.