What are the recommended markers or screening methods for detecting colon cancer?

Recommended Markers and Screening Methods for Colorectal Cancer

For colorectal cancer screening in average-risk adults, multiple effective options are available including colonoscopy, fecal immunochemical testing (FIT), and multitarget stool DNA-FIT, with colonoscopy being the most sensitive single test for detecting both cancer and precancerous polyps. 1

Screening Options by Effectiveness

Stool-Based Tests

• Fecal Immunochemical Test (FIT)

  • Superior to traditional guaiac-based FOBT in sensitivity for detecting colorectal cancer (73.3% vs 33.3%) with similar specificity (>95%) 1
  • Requires only 1-2 samples (vs 3 for gFOBT)
  • No dietary or medication restrictions required
  • Recommended annually 1
  • Higher participation rates compared to gFOBT (approximately 20% greater) 1

• Multitarget Stool DNA-FIT (sDNA-FIT)

  • Higher sensitivity than FIT alone for cancer (92.3% vs 73.8%) and advanced adenomas (42.4% vs 23.8%) 1
  • Significantly better at detecting sessile serrated polyps (42% vs 5%) 1
  • Lower specificity than FIT alone (86.6% vs 94.9%) 1
  • Recommended every 1-3 years 1

• High-Sensitivity Guaiac FOBT (HS-gFOBT)

  • Lower sensitivity compared to FIT 2
  • Requires dietary restrictions
  • Recommended annually 1

Direct Visualization Tests

• Colonoscopy

  • Most sensitive test for detecting both cancer and precancerous polyps 1
  • Allows for removal of polyps during the procedure
  • Recommended every 10 years for average-risk individuals 1
  • Only recommended method for high-risk patients 1
  • Highest risk of complications compared to other screening methods 1

• Flexible Sigmoidoscopy

  • Better detection of advanced adenomas compared to FIT alone 1
  • Examines only lower third to half of the colon 1
  • Recommended every 5 years, or every 10 years with annual FIT 1

• CT Colonography

  • Included in USPSTF recommendations but not currently endorsed by NCCN 1
  • Recommended every 5 years 1

Screening Recommendations by Age

• Ages 45-75: All average-risk adults should be screened 1
• Ages 76-85: Decision should be individualized based on health status and screening history 1
• Ages >85: Screening not recommended 1

Key Considerations for Test Selection

1. Sensitivity for detecting cancer and advanced adenomas:

   • Colonoscopy > sDNA-FIT > FIT > HS-gFOBT 1, 2

2. Ability to detect and remove precancerous polyps:

   • Direct visualization tests (especially colonoscopy) are superior for prevention 1

3. Patient adherence:

   • FIT has higher adherence rates than gFOBT 1
   • Patient preference significantly impacts screening completion 1

4. Risk profile:

   • For high-risk patients (personal/family history of colorectal cancer, adenomatous polyps, inflammatory bowel disease), colonoscopy is the only recommended screening method 1

Important Clinical Caveats

• A positive stool-based test must be followed up with colonoscopy 1
• Digital rectal examination alone or testing a single stool specimen from digital rectal exam is NOT an adequate screening strategy 1
• The "best screening test is the one that gets done" - patient preference should be considered to maximize adherence 1
• Black adults and American Indian/Alaskan Native adults have higher incidence rates of colorectal cancer and may benefit from more aggressive screening approaches 1

By implementing appropriate colorectal cancer screening according to these guidelines, mortality from colorectal cancer can be significantly reduced through both early detection and prevention.