Colorectal cancer is cancer that starts in the colon or the rectum. The colon and rectum comprise the large intestine, which is part of the digestive system. Most often, colorectal cancers start as a growth, called a polyp, on the inner lining of the colon or the rectum. Some types of polyps can change into cancer over time. If cancer forms in a polyp, it can grow into the wall of the colon or the rectum. Once cancer cells are in the wall, they can grow into blood vessels or lymph nodes and spread throughout the body.
Colorectal cancer is the second-leading cause of cancer deaths in the United States, yet it is also one of the most preventable and treatable cancers. The American cancer society recommends all average-risk adults 45 years of age and older get screened. There are two main types of screening:
- Stool-based tests*: Tests that check the stool for signs of cancer (altered DNA, blood in the stool). These tests are less invasive but have to be done more frequently. You are NOT eligible for a stool-based test if you are at high-risk for colorectal cancer. You are considered high-risk if you have any of the following:
- A history of adenomas
- Inflammatory bowel disease and certain hereditary symptoms
- A family history of colorectal cancer
- Colonoscopy: This test looks at the structure of the colon and rectum for any abnormalities. The test is done with a scope (a tube like-instrument with a light and tiny video camera on the end) that is put into the rectum. This test is more invasive but does not have to be done as frequently.
*If you are screened with a test other than a colonoscopy, you should follow up on any abnormal result with a timely colonoscopy.
Talk to your provider about which screening option makes the most sense for you based on your health history and risk factors. No matter what screening option you choose, the most important thing is to get screened.