What are the recommended guidelines for colorectal cancer screening?

Colorectal Cancer Screening Recommendations

When to Start Screening

Average-risk adults should begin colorectal cancer screening at age 45 years, with colonoscopy every 10 years or annual fecal immunochemical testing (FIT) as first-line options. 1, 2

• The American Cancer Society updated their recommendation to age 45 in recognition of rising colorectal cancer incidence in younger adults and similar rates of advanced neoplasia in 45-49 year-olds compared to historical 50-year-old cohorts 2
• The U.S. Multi-Society Task Force maintains age 50 as the starting point for average-risk individuals, though this represents older guidance from 2017 3, 4
• African Americans should begin screening at age 45 due to higher disease burden and earlier onset of disease 3, 5, 1

High-Risk Individuals Require Earlier Screening

For patients with a first-degree relative diagnosed with colorectal cancer or advanced adenoma before age 60, or two first-degree relatives at any age, begin colonoscopy at age 40 OR 10 years before the youngest affected relative's diagnosis, whichever comes first. 3, 5, 1, 2

• Repeat colonoscopy every 5 years in these higher-risk family history patients 3, 2
• If a single first-degree relative was diagnosed at age 60 or older, begin average-risk screening options at age 40 3
• Documentation of "advanced adenoma" in family members requires actual pathology reports or surgical records—do not intensify screening based on vague reports of "polyps" without confirmation 3

Screening Test Selection

First-Tier Options (Choose One)

Colonoscopy every 10 years and annual FIT are the cornerstone screening tests and should be offered first. 3, 1, 2, 4

• Colonoscopy every 10 years provides both detection and removal of precancerous lesions in a single procedure 3, 1, 2
• Annual FIT is preferred in organized screening programs and for patients who decline colonoscopy 3, 1, 2

Second-Tier Options (When First-Tier Tests Declined)

Offer these tests sequentially if patients refuse both colonoscopy and FIT: 3, 4

• CT colonography every 5 years 3, 1
• Multitarget stool DNA test (FIT-DNA) every 3 years 3, 1, 2
• Flexible sigmoidoscopy every 5-10 years (can be combined with FIT every 2 years) 3, 1
• High-sensitivity guaiac-based fecal occult blood test (HSgFOBT) annually 1

Tests to Avoid

• Do not use Septin9 serum assay for screening due to insufficient evidence 3, 4
• Capsule colonoscopy is third-tier only when all other options are declined 3

Critical Follow-Up Requirement

All positive non-colonoscopy screening tests MUST be followed by timely diagnostic colonoscopy—failure to do so negates the entire benefit of screening. 1, 2

When to Stop Screening

Discontinue screening at age 75 in patients who are up-to-date with prior negative screening tests, particularly colonoscopy. 3, 5, 1, 2

• Stop screening when life expectancy falls below 10 years regardless of age 3, 5, 1, 2
• For adults aged 76-85 without prior screening, consider screening based on comorbidities and life expectancy, but this is a weak recommendation 3, 1
• Discourage screening beyond age 85 as harms outweigh benefits 1, 2

Quality Metrics for Colonoscopy

Physicians performing screening colonoscopy must monitor and report quality indicators: 2

• Cecal intubation rates should exceed 90% in screening populations 2
• Withdrawal time should be at least 6 minutes 2
• Adenoma detection rates should be at least 25% in men and 15% in women over 50 2
• Track complication rates and appropriate follow-up intervals 1, 2

Common Pitfalls to Avoid

• Patients under age 50 with colorectal bleeding symptoms (hematochezia, unexplained iron deficiency anemia, melena) require diagnostic colonoscopy, not screening—this is a strong recommendation 3
• Inadequate bowel preparation reduces colonoscopy effectiveness and should trigger repeat examination 1
• Assuming family members had "advanced adenomas" without pathology documentation leads to unnecessary intensive screening 3
• Continuing screening in patients over 75 who are up-to-date with negative tests exposes them to unnecessary procedural risks 3, 1
• Variability in colonoscopy quality between providers significantly impacts screening effectiveness—choose high-quality endoscopists 1

Sequential Screening Approach

When offering multiple options: 3, 4

1. Offer colonoscopy first as the preferred prevention test
2. Offer FIT to patients who decline colonoscopy
3. Offer second-tier tests (CT colonography, FIT-DNA, flexible sigmoidoscopy) to patients who decline both colonoscopy and FIT
4. Consider risk-stratified approach: colonoscopy for higher pretest probability populations, FIT for lower-risk populations 3