At what age should colon cancer screening start?

Colorectal Cancer Screening Age Guidelines

Colorectal cancer screening should begin at age 45 for average-risk individuals, with screening continuing through age 75 for those in good health with life expectancy greater than 10 years. 1, 2

Starting Age for Screening

• Average-risk individuals:

  • Begin screening at age 45 (Grade B recommendation from USPSTF, qualified recommendation from ACS) 1, 2
  • This represents an update from previous guidelines that recommended starting at age 50 2
  • The recommendation to lower the starting age reflects increasing rates of colorectal cancer in younger adults

• Higher-risk individuals:

  • Family history of CRC or advanced adenoma in first-degree relative diagnosed before age 60: Begin screening at age 40 or 10 years before the youngest affected relative's diagnosis, whichever is earlier 1
  • First-degree relative diagnosed with CRC at ≥60 years: Begin screening at age 40 3
  • African Americans: Begin screening at age 45 (same as current general population recommendation) 1

Screening Test Options

Tier 1 (preferred) options:

• Colonoscopy every 10 years
• Annual fecal immunochemical test (FIT)

Tier 2 options:

• CT colonography every 5 years
• FIT-fecal DNA test every 3 years
• Flexible sigmoidoscopy every 5-10 years

Tier 3 option:

• Capsule colonoscopy every 5 years

When to Stop Screening

• Ages 76-85: Individualize screening decisions based on:

  • Prior screening history (those never screened may benefit more)
  • Overall health status
  • Life expectancy (consider stopping if <10 years)
  • Patient preferences 2, 1

• Age >85: Discontinue screening (benefits outweighed by risks) 2, 1

Important Clinical Considerations

• All positive results on non-colonoscopy screening tests must be followed up with timely colonoscopy 1
• Patients with colorectal bleeding symptoms should undergo colonoscopy regardless of age or screening status 1
• The 10-year cumulative risk for average-risk population at age 50 is 0.44% 4
• Individuals with family history of CRC reach this equivalent risk level 3-29 years earlier than the general population, depending on the specific family history 4

Pitfalls and Caveats

1. Don't miss high-risk individuals: Those with family history require earlier and more frequent screening.

2. Don't ignore symptoms: Patients with colorectal bleeding symptoms should undergo diagnostic colonoscopy regardless of age or screening status.

3. Consider life expectancy: Screening should be discontinued when potential harms outweigh benefits, typically at age 75 for those with negative prior screenings or when life expectancy is <10 years.

4. Ensure follow-up: All positive non-colonoscopy screening tests must be followed up with colonoscopy to complete the screening process.

5. Consider screening burden: When selecting a screening modality, discuss the frequency, preparation requirements, and potential complications with patients to improve adherence.