At what age should I start colonoscopy (colon cancer screening) screenings?

Colorectal Cancer Screening Recommendations

Colorectal cancer screening should begin at age 45 for all average-risk individuals, with colonoscopy every 10 years or annual FIT as the preferred first-tier screening options. 1

Screening Age Guidelines

When to Start Screening

• Average-risk individuals: Begin at age 45 (Grade B recommendation for ages 45-49; Grade A recommendation for ages 50-75) 1
• African Americans: Begin at age 45 (current guidelines no longer recommend different starting ages based on race) 1
• Higher-risk individuals:
  • With first-degree relative diagnosed with CRC or advanced adenoma before age 60: Begin at age 40 or 10 years before the youngest affected relative's diagnosis (whichever is earlier) 1
  • With single first-degree relative diagnosed at ≥60 years with CRC or advanced adenoma: Begin at age 40 2

When to Stop Screening

• Consider stopping at age 75 if up-to-date with negative prior screening tests, particularly high-quality colonoscopy 1
• For individuals without prior screening, consider screening up to age 85, depending on comorbidities and life expectancy 3
• Discourage screening beyond age 85 due to increased mortality risk and adverse events associated with colonoscopy 1

Recommended Screening Methods

First-Tier Options (Strongly Recommended)

1. Colonoscopy every 10 years (strong recommendation, moderate-quality evidence)
2. Annual Fecal Immunochemical Test (FIT) (strong recommendation, moderate-quality evidence)

Second-Tier Options (For Those Who Decline First-Tier Tests)

• Flexible sigmoidoscopy every 5-10 years
• CT colonography every 5 years
• FIT-fecal DNA every 3 years
• Capsule colonoscopy every 5 years (weak recommendation)

Special Considerations

Symptomatic Patients

• 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 3

Risk Stratification Approach

• Colonoscopy is preferred in populations with higher prevalence of advanced neoplasia
• FIT screening may be appropriate in populations with lower prevalence of advanced neoplasia 2

Effectiveness of Screening

• Evidence shows that screening in the 50-59 age group detects significantly more colorectal neoplasia compared to the 40-49 age group (22.6% vs. 12.1%) 4
• The number needed to screen to detect one advanced lesion is 20 in those aged 50-59 compared to 49 in those aged 40-49 4

Implementation Strategy

1. Offer colonoscopy as the first option
2. For patients who decline colonoscopy, offer FIT
3. For patients who decline both first-tier options, discuss second-tier tests
4. Ensure all positive results on non-colonoscopy screening tests are followed up with timely colonoscopy 1

Common Pitfalls to Avoid

• Delaying screening beyond age 45 in average-risk individuals
• Failing to follow up positive non-colonoscopy screening tests with colonoscopy
• Overlooking symptoms such as rectal bleeding, unexplained anemia, or melena regardless of age
• Continuing screening beyond age 75 in patients with prior negative screening and limited life expectancy
• Using inappropriate screening intervals (e.g., performing colonoscopy more frequently than every 10 years in average-risk individuals with normal findings)