In an update to its 2009 guidelines, the American College of Gastroenterology (ACG) suggested screening for colorectal cancer in average-risk adults ages 45 to 49 years.
The conditional recommendation, which lowers the suggested screening age, is based on low-quality evidence. The ACG continues to make a strong recommendation based on moderate-quality evidence for screening in average-risk adults ages 50 to 75 years. The new guidelines were published in the March American Journal of Gastroenterology and were based on studies published through October 2020 in adults ages 40 years and older.
The ACG recommended colonoscopy and fecal immunochemical testing (FIT) as primary screening tests but suggested that in individuals unwilling or unable to undergo them, flexible sigmoidoscopy, multitarget stool DNA tests, CT colonography, or colon capsule should be considered. The guidelines suggested against septin 9 as a screening test.
Recommended screening intervals are one year for FIT and 10 years for colonoscopy. Suggested intervals for other screening methods are three years for multitarget stool DNA test, five to 10 years for flexible sigmoidoscopy, and every five years for both CT colonography and colon capsule. The ACG suggested that decisions to continue screening after age 75 years should be individualized.
The guidelines also offered recommendations on screening in individuals with a family history of colorectal cancer or advanced polyps, as well as on quality indicators for different methods of testing, use of aspirin for chemoprevention, and interventions to improve adherence to screening and follow-up colonoscopy.
The authors of the guidelines noted that although many public health initiatives have addressed colorectal cancer screening and there are many screening tests available for colorectal cancer, screening rates remain low among eligible U.S. adults.
“Acknowledging the available screening tools for use in the correct settings of each population will increase the compliance of different populations,” they wrote. “Consistent with this goal, adoption of cost-effective, highly accurate, noninvasive methodologies associated with reduced complications and barriers than more invasive methods may improve overall acceptance of the screening process.”