The National Cancer Institute (NCI) published an article indicating that since the mid-1980 and 1990's, colon cancer incidence rates have decreased in individuals 55 and older, while increasing in adults ages 20-50. This new evidence has prompted a discussion as to whether screening should start earlier than the current recommendation of 50 years old in a person with average risk. Recommendations for earlier screening have already been established for high-risk individuals, i.e. individuals with a first degree relative diagnosed with colorectal cancer before age 60.
With the exclusion of skin cancers, the American Cancer Society reports colorectal cancer as the third most common cancer diagnosed in both men and women in the United States. The lifetime risk of developing colorectal cancer is about 1 in 21 for men and 1 in 23 for women; therefore earlier screening may increase prevention and lower the lifetime risks.
Individuals with a personal and/or family history of an inherited colorectal cancer syndrome have a higher risk than the general population to develop colorectal cancer, therefore screening is recommended at a much earlier age which can be specific to each syndrome. There are several syndromes associated with hereditary colorectal cancer. The three most common are Lynch syndrome, familial adenomatous polyposis (FAP), and MYH-associated polyposis (MAP), which account for up to 5% of all colon cancer cases.