The American Cancer Society recommends that people at average risk for colorectal cancer should start regular screening at age 45. The starting age was recently lowered from 50 because of an increase in this cancer among younger people. Individuals with risk factors, such as a family history, can discuss earlier screening with their provider. Adults in good health should continue screening until at least age 75.
There are several options for screening, including colonoscopies every 10 years, flexible sigmoidoscopy (an exam of the lower part of the colon and rectum) every five years, stool DNA tests (such as Cologuard) every three years or tests that detect blood in the stool (such as fecal immunochemical testing, or FIT) every year. Positive stool tests should be followed up with a colonoscopy.
Colonoscopies and sigmoidoscopies require a special diet and preparation to empty your bowels. For stool tests, you usually collect a fecal sample using a kit and send it to a lab. All of these methods can detect early colon cancer or precancerous changes known as polyps. The best test is the one you actually use!