Colorectal Cancer Screening Guidelines
Colorectal cancer screening should begin at age 45 for average-risk adults with either a high-sensitivity stool-based test or a structural examination, with all positive non-colonoscopy screening tests followed by timely colonoscopy. 1
Screening Age Recommendations
Average-Risk Individuals:
- Begin screening at age 45 for all average-risk adults 1
- Continue regular screening through age 75 for those in good health with life expectancy >10 years 1
- For adults aged 76-85, individualize screening decisions based on patient preferences, life expectancy, health status, and prior screening history 1
- Discourage screening in individuals over age 85 1
High-Risk Individuals:
- Begin screening at age 40 (or 10 years before the youngest affected relative's diagnosis) for those with:
- For African Americans, screening may begin at age 45 due to higher disease burden 1
- For those with inflammatory bowel disease (ulcerative colitis or Crohn's disease): colonoscopy every 1-2 years starting 8 years after pancolitis onset or 12-15 years after left-sided colitis onset 1
- For those with familial adenomatous polyposis (FAP): annual flexible sigmoidoscopy beginning at age 10-12 years with genetic counseling 1
- For those with hereditary nonpolyposis colorectal cancer (HNPCC/Lynch syndrome): colonoscopy every 1-2 years beginning at age 20-25 or 10 years before youngest case in family 1
Recommended Screening Tests
Tier 1 (Preferred) Tests:
Tier 2 Tests:
- High-sensitivity guaiac-based fecal occult blood test (HSgFOBT) annually 1
- Multitarget stool DNA test (mt-sDNA/FIT-DNA) every 3 years 1
- CT colonography every 5 years 1
- Flexible sigmoidoscopy every 5 years 1
Test Characteristics:
- Structural (visual) examinations can detect both cancer and precancerous polyps:
- Colonoscopy (every 10 years)
- CT colonography (every 5 years)
- Flexible sigmoidoscopy (every 5 years)
- Stool-based tests primarily detect cancer:
- FIT (annually)
- HSgFOBT (annually)
- Multitarget stool DNA (every 3 years) 1
Implementation Considerations
- All positive results from non-colonoscopy screening tests must be followed up with timely colonoscopy 1
- Patient preference is an important consideration when selecting a screening method 1
- The quality of colonoscopy is critical for effective screening and should be monitored using quality indicators such as:
- Cecal intubation rates
- Withdrawal time
- Adenoma detection rates
- Appropriate follow-up intervals
- Complication rates 1
- For patients who decline colonoscopy, FIT should be offered as an alternative 2
- A risk-stratified approach may be appropriate, with FIT screening in populations with estimated low prevalence of advanced neoplasia and colonoscopy screening in high prevalence populations 2, 3
Common Pitfalls and Caveats
- Failure to follow up positive stool-based tests with colonoscopy negates the benefit of screening 1
- Inadequate bowel preparation can reduce colonoscopy effectiveness 1
- Discontinuing screening too early in healthy individuals or continuing too long in those with limited life expectancy can lead to unnecessary risks 1
- Variability in colonoscopy quality can significantly impact screening effectiveness 1
- Young adults (<50 years) with suspected colorectal bleeding should receive thorough diagnostic evaluation due to rising CRC incidence in this age group 2, 4
- Any screening is better than no screening - patient preferences and local resource availability should be considered to increase screening uptake 3