What are the guidelines for colon polyp screening?

Colon Polyp Screening Guidelines

For average-risk individuals, colorectal cancer screening should begin at age 50 with either colonoscopy every 10 years or annual fecal immunochemical testing (FIT), as these are the cornerstone screening modalities with the strongest evidence for reducing colorectal cancer mortality. 1

Risk Stratification for Screening

Average Risk (70-80% of cases)

• Begin screening at age 50 1
• Recommended screening options:
  • Colonoscopy every 10 years (preferred primary method) 1
  • Annual fecal immunochemical test (FIT) 1
  • Annual guaiac-based fecal occult blood test (FOBT) 1
  • Flexible sigmoidoscopy every 5 years (can be combined with annual stool-based testing) 1
  • CT colonography every 5 years (emerging option) 1

Moderate Risk (15-20% of cases)

• History of adenomatous polyps:

  • Total colon examination (colonoscopy) within 3 years after initial polyp removal 1
  • If follow-up is normal and original polyp was <1 cm without villous histology, return to average-risk screening 1
  • If original polyp was ≥1 cm or had villous histology, continue total colon examination every 5 years 1

• Family history of colorectal cancer or adenomas:

  • Begin screening at age 40 or 10 years before the youngest case in the family, whichever is earlier 1
  • Total colon examination every 5 years 1
  • Higher risk if first-degree relative diagnosed before age 60 or if multiple first-degree relatives affected at any age 1, 2

High Risk (5-10% of cases)

• Familial adenomatous polyposis (FAP):

  • Begin surveillance with flexible sigmoidoscopy at puberty 1
  • Consider genetic testing and counseling 1
  • If genetic test positive, consider colectomy or endoscopy every 1-2 years 1

• Hereditary non-polyposis colorectal cancer (HNPCC/Lynch Syndrome):

  • Begin colonoscopy at age 21 1
  • Screening interval: every 2 years until age 40, then annually 1
  • Consider genetic testing and counseling 1

• Inflammatory bowel disease:

  • Begin colonoscopy 8 years after onset of pancolitis or 12-15 years after onset of left-sided colitis 1
  • Continue surveillance every 1-2 years 1

Quality Considerations for Colonoscopy

• Important quality indicators include: 1
  • Cecal intubation rates (should exceed 95%) 3
  • Adequate withdrawal time 1
  • Adenoma detection rates (should exceed 25% in men and 15% in women) 3
  • Appropriate bowel preparation 1, 3
  • Standardized reporting of findings 1
  • Documentation of follow-up plans 1

Stool-Based Testing Considerations

• Guaiac-based testing requires three successive stool specimens annually 1
• FIT detects human globin and requires only a single stool sample annually 1
• Any positive stool test requires follow-up with colonoscopy 1
• Stool DNA testing is an emerging option but interval for screening remains uncertain 1

CT Colonography Considerations

• Accuracy comparable to colonoscopy for lesions >10 mm 1
• Less accurate for lesions 5-9 mm 1
• Cannot reliably identify lesions <5 mm 1
• All identified lesions >5 mm should be referred for colonoscopy 1

Screening Discontinuation

• Consider discontinuing screening at age 75 for individuals with prior negative screening 2
• Persons without prior screening may be considered for screening up to age 85, depending on comorbidities 2

Emerging Trends

• Recent evidence suggests potential benefit of beginning screening at age 45, particularly for African Americans 1, 4
• Newer screening modalities under investigation include blood-based tests, colon capsule endoscopy, and stool microbiome testing 5

The effectiveness of colorectal cancer screening is significantly impacted by compliance rates. Even with imperfect compliance (60%), screening significantly reduces colorectal cancer mortality at costs comparable to other cancer screening procedures 6.