Colonoscopy Screening Ages
For average-risk individuals without family history, begin colonoscopy screening at age 50 years (age 45 for African Americans), and for those with a family history of colon cancer, begin at age 40 or 10 years before the youngest affected relative's diagnosis age, whichever comes first. 1
Average-Risk Screening (No Family History)
Start colonoscopy at age 50 for non-African Americans with no personal or family history of colorectal cancer, polyps, or inflammatory bowel disease. 1 This represents a strong recommendation based on moderate-quality evidence from the U.S. Multi-Society Task Force. 1
African Americans should begin screening at age 45 years due to higher incidence rates and earlier onset of colorectal cancer in this population. 1 This is a weaker recommendation based on very-low-quality evidence, but reflects the rising incidence in younger populations. 1
Screening intervals: Colonoscopy every 10 years or annual fecal immunochemical testing (FIT) are the first-line options. 1, 2 Colonoscopy has advantages in opportunistic screening settings, while FIT may be preferred in organized programs. 1
Family History of Colon Cancer: Risk-Stratified Approach
Single First-Degree Relative Diagnosed at Age ≥60
Begin screening at age 40 using average-risk screening options (colonoscopy every 10 years or annual FIT). 3, 2 These individuals have modestly elevated risk (approximately 1.9-3.4 times higher than general population) but the risk curve parallels average-risk individuals, occurring about 10 years earlier. 3
Single First-Degree Relative Diagnosed at Age <60
Begin colonoscopy at age 40 OR 10 years before the relative's diagnosis age, whichever comes first, and repeat every 5 years. 1, 3 This more intensive surveillance reflects the significantly higher risk when cancer occurs at younger ages in relatives. 1
For example, if your parent was diagnosed at age 52, you should begin colonoscopy at age 40 (not age 42), repeating every 5 years. 3
Two or More First-Degree Relatives with Colon Cancer at Any Age
Begin colonoscopy at age 40 OR 10 years before the youngest affected relative's diagnosis, whichever comes first, and repeat every 3-5 years. 1 The risk is approximately 3-4 times higher than the general population when multiple relatives are affected. 3
Critical consideration: If multiple relatives have cancer diagnosed before age 50, or if there are cancers across multiple generations, genetic counseling and testing for Lynch syndrome or familial adenomatous polyposis should be pursued. 3, 4 Lynch syndrome requires colonoscopy every 1-2 years starting 10 years before the youngest affected relative's diagnosis. 3
Family History of Adenomatous Polyps
If a first-degree relative had adenomatous polyps diagnosed at age <60, begin colonoscopy at age 40 or 10 years before their diagnosis age, whichever comes first, repeating every 5 years. 4 This follows the same algorithm as for colon cancer diagnosed before age 60. 4
If a first-degree relative had adenomatous polyps diagnosed at age ≥60, begin screening at age 40 using average-risk options. 4 The risk is approximately 1.9 times higher than those without family history. 4
When to Stop Screening
Consider stopping screening at age 75 if up to date with prior negative tests, particularly colonoscopy, or when life expectancy is less than 10 years. 1 This is a weak recommendation based on low-quality evidence. 1
For individuals without prior screening, consider screening up to age 85 depending on comorbidities and life expectancy. 1 Beyond age 85, screening is not recommended. 1
Diverticulitis and Colonoscopy Timing
A history of diverticulitis does NOT change the age to begin routine screening colonoscopy. Follow the standard age recommendations above based on family history status.
After an acute diverticulitis episode: The traditional recommendation to perform colonoscopy 6-8 weeks after resolution has been challenged by recent evidence. 5, 6, 7 In patients under age 50 with uncomplicated diverticulitis confirmed by CT scan, cancer detection rates are extremely low (0% in multiple studies). 5, 7
Colonoscopy after diverticulitis should be reserved for: patients over age 70, those with complicated diverticulitis (abscess, perforation), those with alarm symptoms (hematochezia, iron deficiency anemia, weight loss), or when CT findings are equivocal for malignancy. 8 Modern high-resolution CT scanning is often sufficient to exclude cancer in straightforward uncomplicated cases. 6
Common Pitfalls to Avoid
Verify family history details whenever possible. Family history information is often incomplete or inaccurate regarding the exact diagnosis (cancer vs. polyps) and age at diagnosis. 3, 4 These details critically determine screening intensity.
Do not delay colonoscopy in symptomatic patients. Any patient with hematochezia, melena, unexplained iron deficiency anemia, or significant change in bowel habits requires diagnostic colonoscopy regardless of age or screening status. 1, 2 These are not screening scenarios.
Distinguish between screening and surveillance. Patients with personal history of polyps or cancer require surveillance colonoscopy at different intervals (typically 3-5 years depending on polyp characteristics), not routine screening intervals. 3