Among cancers that affect both men and women, colorectal cancer is the second leading cancer cause of death in the United States. This type of cancer (also known as colon cancer) occurs in the colon or in the rectum. A person’s risk of developing colorectal cancer increases as he or she gets older, and the disease occurs most often in people age 50 and above. 

Screening for prevention and early detection
Screening tests can help prevent colorectal cancer by finding polyps,

abnormal growths in the colon or rectum, so that they can be removed before they become cancerous. Screening also can find colorectal cancer early, when treatment works best. For most people, screening for colorectal cancer should begin at age 50 and continue regularly.

Family history is an important risk factor

Most colorectal cancer is caused by the complex interaction of many genes and behavioral risk factors, such as being overweight and physically inactive. In addition, scientists have discovered specific gene abnormalities (mutations) that contribute to the development of some rare types of hereditary colorectal cancer.* These rare cancers typically occur at an earlier age than other types of colorectal cancer that are not considered hereditary.

People with a family history of colorectal cancer are at an increased  risk of developing this disease. Health care providers can help patients evaluate their family histories to determine which screening tests are best for them.  

*Familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer.

The information on this page was compiled as a collaborative effort by CDC's National Office of Public Health Genomics and the Division of Cancer Prevention and Control at CDC's National Center for Chronic Disease Prevention and Health Promotion. Please direct any specific questions or inquires about colorectal cancer to the Division of Cancer Prevention and Control.