From the Guidelines
The general recommendation is to begin regular colonoscopy screening at age 45 for average-risk individuals, continuing until age 75, as supported by the most recent guidelines from the American Cancer Society, 2018, and the National Comprehensive Cancer Network, 2022, as well as the US Multi-Society Task Force on Colorectal Cancer 1. After age 75, the decision to screen should be individualized based on health status and life expectancy, with most people stopping screening by age 85. For those with a family history of colorectal cancer or advanced polyps, screening should begin earlier—typically at age 40 or 10 years before the youngest affected relative's diagnosis, whichever comes first, as recommended by the National Comprehensive Cancer Network, 2022, and the US Multi-Society Task Force on Colorectal Cancer 1. Some key points to consider include:
- Average-risk adults in good health with a life expectancy of more than 10 years should begin screening at age 45 with any test, as recommended by the American Cancer Society, 2018, and the National Comprehensive Cancer Network, 2022 1.
- Adults between ages 50 and 75 years should be screened with any test, with a strong recommendation for colonoscopy every 10 years or FIT every 1 year as primary screening modalities, as recommended by the American College of Gastroenterology, 2021 1.
- African Americans may benefit from starting screening at age 45 due to higher risk, as suggested by the US Multi-Society Task Force on Colorectal Cancer, 2017 1.
- High-risk individuals with inflammatory bowel disease, certain genetic syndromes, or a personal history of colorectal cancer need more frequent screening beginning at younger ages. These guidelines balance the benefits of detecting and preventing colorectal cancer against the risks of the procedure, which include bleeding, perforation, and complications from sedation, as discussed in the US Multi-Society Task Force on Colorectal Cancer, 2017 1. The timing recommendations reflect the fact that colorectal cancer typically develops slowly over years, with risk increasing with age, while the benefits of screening diminish as life expectancy decreases in very elderly patients. It's worth noting that the most recent and highest quality study, the AGA clinical practice update on risk stratification for colorectal cancer screening and post-polypectomy surveillance, 2023, provides a comprehensive review of the current guidelines and recommendations for colorectal cancer screening 1.
From the Research
Age Guidelines for Colonoscopy
- The American Cancer Society recommends screening for colorectal cancer in asymptomatic individuals over the age of 50 2.
- A study published in the Journal of the National Cancer Institute in 1993 found that screening for colorectal cancer using fecal occult blood testing and sigmoidoscopy in individuals aged 40 and older can increase the likelihood of early detection of the disease 3.
- Another study published in the Journal of the Formosan Medical Association in 2002 compared colonoscopy, sigmoidoscopy, and fecal occult blood tests for colorectal cancer screening in asymptomatic adults and found that colonoscopy can detect neoplastic lesions undetectable by FOBT and sigmoidoscopy 4.
- A systematic review and network meta-analysis published in BMJ Open in 2019 found that sigmoidoscopy, annual and biennial guaiac faecal occult blood test (gFOBT) all reduce colorectal cancer mortality, and sigmoidoscopy may reduce colorectal cancer incidence and mortality more in men than in women 5.
- The Cochrane database of systematic reviews published a study in 2013 that compared flexible sigmoidoscopy versus faecal occult blood testing for colorectal cancer screening in asymptomatic individuals and found that both methods reduce colorectal cancer mortality when applied as screening tools 6.
Screening Recommendations
- The majority of the studies recommend screening for colorectal cancer in individuals over the age of 50 3, 2, 5.
- Some studies suggest that screening can start at the age of 40 3.
- The frequency of screening depends on the method used, with annual or biennial screening recommended for fecal occult blood testing 5 and once-only screening recommended for sigmoidoscopy and colonoscopy 6, 5.