Colon cancer screening can detect polyps and early cancers in the large intestine. This type of screening can find problems that can be treated before cancer develops or spreads. Regular screenings may reduce the risk of death and complications caused by colorectal cancer.
There are several ways to screen for colon cancer.
- Polyps in the colon and small cancers can cause small amounts of bleeding that cannot be seen with the naked eye. But blood can often be found in the stool.
- This method checks your stool for blood.
- The most common test used is the fecal occult blood test (FOBT). Two other tests are called the fecal immunochemical test (FIT) and stool DNA test (sDNA).
- This test uses a small flexible scope to view the lower part of your colon. Because the test only looks at the last one third of the large intestine (colon), it may miss some cancers that are higher in the large intestine.
- Sigmoidoscopy and a stool test may be used together.
- A colonoscopy is similar to a sigmoidoscopy, but the entire colon can be viewed.
- Your health care provider will give you the steps for cleansing your bowel. This is called bowel preparation.
- During a colonoscopy, you receive medicine to make you relaxed and sleepy.
- Sometimes, CT scans are used as an alternative to a regular colonoscopy. This is called a virtual colonoscopy.
- Capsule endoscopy involves swallowing a small, pill-sized camera that takes a video of the inside of your intestines. The method is being studied, so it is not recommended for standard screening at this time.
SCREENING FOR AVERAGE-RISK PEOPLE
There is not enough evidence to say which screening method is best. But, colonoscopy is most thorough. Talk to your health care provider about which test is right for you.
Both men and women should have a colon cancer screening test starting at age 50. Some providers recommend that African Americans begin screening at age 45.
Screening options for people with an average risk for colon cancer:
- Colonoscopy every 10 years
- FOBT or FIT every year (colonoscopy is needed if results are positive)
- sDNA every 1 or 3 years (colonoscopy is needed if results are positive)
- Flexible sigmoidoscopy every 5 to 10 years, usually with stool testing FOBT done every 1 to 3 years
- Virtual colonoscopy every 5 years
SCREENING FOR HIGHER-RISK PEOPLE
People with certain risk factors for colon cancer may need earlier (before age 50) or more frequent testing.
More common risk factors are:
- A family history of inherited colorectal cancer syndromes, such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colorectal cancer (HNPCC).
- A strong family history of colorectal cancer or polyps. This usually means close relatives (parent, sibling, or child) who developed these conditions younger than age 60.
- A personal history of colorectal cancer or polyps.
- A personal history of long-term (chronic) inflammatory bowel disease (for example ulcerative colitis or Crohn disease).
Screening for these groups is more likely to be done using colonoscopy.
Screening for colon cancer; Colonoscopy - screening; Sigmoidoscopy - screening; Virtual colonoscopy - screening; Fecal immunochemical test; Stool DNA test; sDNA test; Colorectal cancer - screening; Rectal cancer - screening
Itzkowitz SH, Potack J. Colonic polyps and polyposis syndromes. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology/Diagnosis/Management. 10th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 126.
National Comprehensive Cancer Network (NCCN). NCCN website. Clinical practice guidelines in oncology (NCCN Guidelines) Colorectal cancer screening. Version 2.2017. www.nccn.org/professionals/physician_gls/pdf/colorectal_screening.pdf. Updated November 14, 2017. Accessed January 30, 2018.
US Preventive Services Task Force, Bibbins-Domingo K, Grossman DC, et al. Screening for colorectal cancer: US Preventive Task Force recommendation statement. JAMA. 2016;315(23):2564-2575. PMID: 27304597 www.ncbi.nlm.nih.gov/pubmed/27304597.
Review Date 1/22/2018
Updated by: Jenifer K. Lehrer, MD, Department of Gastroenterology, Aria-Jefferson Health Torresdale, Jefferson Digestive Diseases Network, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.