Almost all cancers of the colon and rectum start as a polyp. A polyp is a small benign or noncancerous growth that occurs in the inner lining of the large intestine. Some of these polyps can slowly grow and transform into cancer. This process typically takes eight to 10 years.
Many polyps and early cancers do not show any signs or symptoms. The goal of screening is either to remove any polyps that may be found in order to reduce the chance of them turning into a cancer or early detection of cancer.
American Cancer Society Guidelines for the Early Detection of Colon and Rectal Cancer
Beginning at age 50, the American Cancer Society recommends men and women follow one of the following five test options:
- Yearly fecal occult blood test (FOBT)
- Flexible sigmoidoscopy every five years
- Yearly FOBT and flexible sigmoidoscopy every 5 years
- Double contrast barium enema every five years
- Colonscopy every 10 years