What are the recommended guidelines for colon cancer screening?

Colorectal Cancer Screening Guidelines

Colorectal cancer screening should begin at age 45 for average-risk individuals, with colonoscopy every 10 years and annual FIT being the preferred first-line screening options. 1

Screening Recommendations by Risk Category

Average-Risk Individuals

• Starting age: 45 years 1
  • Non-African Americans previously recommended to start at age 50 2
  • African Americans recommended to start at age 45 due to higher incidence and mortality rates 2, 1
• Preferred screening options:
  1. Colonoscopy every 10 years 2, 1
  2. Annual FIT (Fecal Immunochemical Test) 2, 1
• Alternative screening options (for those who refuse colonoscopy and FIT):
  • CT colonography every 5 years 2, 1
  • FIT-fecal DNA (Cologuard) every 3 years 2, 1
  • Flexible sigmoidoscopy every 5-10 years 2, 1
  • Capsule colonoscopy (if available) 2

High-Risk Individuals

Family History of CRC or Advanced Adenomas

• One first-degree relative with CRC or advanced adenoma diagnosed before age 60 OR two first-degree relatives at any age:
  • Begin colonoscopy at age 40 or 10 years before youngest affected relative's diagnosis, whichever is earlier 2, 3
  • Repeat every 5 years 2
• One first-degree relative diagnosed at age 60 or older:
  • Begin screening at age 40 2
  • Follow average-risk screening options and intervals 2

Inflammatory Bowel Disease

• Begin colonoscopy 8-10 years after symptom onset 3
• Repeat every 1-3 years 3

Hereditary Syndromes

• Lynch Syndrome:
  • Begin colonoscopy at age 25 3
  • Repeat every 1-2 years 3
• Familial Adenomatous Polyposis:
  • Begin flexible sigmoidoscopy at puberty 2
  • Consider genetic testing and counseling 2
  • If polyposis present, consider colectomy 2

When to Stop Screening

• Consider stopping at age 75 years or when life expectancy is less than 10 years, especially for those with negative prior screening tests 2, 1
• For those without prior screening, consider screening up to age 85, depending on comorbidities and life expectancy 2
• Screening is generally discouraged after age 75 due to increased risks (3.8%-6.8% experiencing emergency visits or hospitalization within 30 days of colonoscopy) 1

Test Performance Characteristics

• Colonoscopy: Superior sensitivity for detecting both CRC and precancerous lesions 1

  • Allows for simultaneous treatment of polyps
  • Small risk of perforation (0.1-0.2%) and bleeding 1
  • Requires bowel preparation and typically sedation 1

• FIT vs. Cologuard comparison 1:

  Test	Sensitivity for CRC	Sensitivity for Advanced Precancerous Lesions	Specificity
  Cologuard	92.3%	42.4%	86.6%
  FIT	73.8%	23.8%	94.9%

Important Clinical Considerations

• All positive stool-based tests must be followed up with diagnostic colonoscopy 1
• Failure to follow up positive tests negates screening benefits 1
• Adults under age 50 with colorectal bleeding symptoms (hematochezia, unexplained iron deficiency anemia, melena with negative upper endoscopy) should undergo colonoscopy regardless of screening recommendations 2
• Quality metrics for colonoscopy include cecal intubation rates, withdrawal time, and adenoma detection rates 1
• While initial costs of colonoscopy are higher than other tests, all recommended screening methods are cost-effective compared to no screening 1

Screening Approach Algorithm

1. Assess risk category (average vs. high-risk)
2. Determine appropriate starting age based on risk factors
3. Offer colonoscopy as first-line option
4. If patient declines colonoscopy, offer FIT
5. If patient declines both, offer second-tier options (CT colonography, FIT-fecal DNA, flexible sigmoidoscopy)
6. Ensure appropriate follow-up of any positive screening test with diagnostic colonoscopy
7. Reassess screening needs at age 75 based on prior screening history and life expectancy