Colorectal Cancer Screening
Countless breakthroughs in modern technology make colon cancer detection more accessible than ever. Prevention and screening tools include those that can find colorectal polyps as well as cancer—some can do both. People with certain risk factors should begin screening earlier or have screening more often.
Tests that can detect polyps and cancer examine at the structure of the colon itself to identify any abnormal areas. They are done either with a scope put into the rectum or with special imaging tests. Polyps found during these procedures can be removed, so these tests may prevent colorectal cancer.
These tests are preferred if they are available and you are willing to have them, and include:
- Flexible Sigmoidoscopy: A thin, flexible, lighted tube with a small video camera on the end is put into the rectum to view the rectum and the lower part of the colon. If an abnormality is seen, it can be biopsied or removed. Less than half of the colon can be seen with this procedure.
- Colonoscopy: Similar to a flexible sigmoidoscopy, a colonoscopy allows the entire length of the colon and rectum to be viewed. Any abnormalities can be biopsied or removed.
- Double-Contrast Barium Enema: In this x-ray test, air and a chalky liquid called barium sulfate are put into the colon and rectum to outline the inner lining. If suspicious areas are identified, a colonoscopy will be recommended to explore them.
- CT Colonography: Also known as virtual colonoscopy, this test is an advanced type of computerized tomography (CT) scan of the colon and rectum. Special computer programs create both 2D and 3D views of the inside of the colon and rectum. This exam may be useful for people who can’t—or don’t want to—have more invasive tests.
Tests that assess stool samples can detect signs of cancer. While they are less invasive and easier to have done, they are less likely to detect polyps. These include:
- Fecal Occult Blood Test (FOBT): This test detects hidden blood in the stool through a chemical reaction, but cannot tell if the blood is from the colon or from other parts of the digestive tract.
- Fecal Immunochemical Test (FIT): Similar to an FOBT, this test detects hidden blood in the stool, but through a different chemical reaction.
- Cologuard® Colon Cancer Test: This exam detects hidden blood in the stool, as well as abnormal cell associated with colon cancer and precancerous polyps.
Other screening options for those who cannot have a colonoscopy for medical reasons include:
- Yearly fecal occult blood test or fecal immunochemical test (FIT)
- Flexible sigmoidoscopy every five years
- Yearly stool blood test plus flexible sigmoidoscopy every five years (preferred)
- Double contrast barium enema every five years
- An endoscopic ultrasound also may be used. If any polyps are found they should be removed if possible.
- While a digital rectal exam (DRE) is often done as part of a regular physical exam, it should not be used as a stand-alone test for colorectal cancer. For a DRE, the doctor examines the patient’s rectum with a gloved finger.
Talk to your doctor about your own risk and when you should have screening tests. Learn more about colon cancer diagnosis, treatment options and current clinical trials.