What are the guidelines for colorectal cancer screening?

Guidelines for Colorectal Cancer Screening

Clinicians should screen for colorectal cancer in average-risk adults starting at age 50 years and in high-risk adults starting at age 40 years or 10 years younger than the age at which the youngest affected relative was diagnosed with colorectal cancer. 1

Risk Assessment and Screening Initiation

• All adults should undergo individualized risk assessment for colorectal cancer to determine appropriate screening age and method 1
• Average-risk adults should begin screening at age 50 years 1
• African Americans should begin screening at age 45 years due to higher disease burden 1, 2
• High-risk individuals should begin screening at age 40 years or 10 years before the youngest affected relative's diagnosis, whichever comes first 1, 2
• High-risk factors include:
  • First-degree relative with colorectal cancer or advanced adenoma diagnosed before age 60 1, 2
  • Two or more first-degree relatives with colorectal cancer or advanced adenoma 1
  • Personal history of inflammatory bowel disease (ulcerative colitis or Crohn's disease) 1
  • Hereditary syndromes such as Lynch syndrome (HNPCC) or familial adenomatous polyposis 1

Recommended Screening Methods

For Average-Risk Individuals

• Stool-based tests:
  • Fecal immunochemical test (FIT) annually 1, 2
  • High-sensitivity guaiac-based fecal occult blood test (gFOBT) annually 1, 2
  • Multitarget stool DNA test (FIT-DNA) every 3 years 2
• Structural examinations:
  • Colonoscopy every 10 years 1, 2
  • Flexible sigmoidoscopy every 5 years 1, 2
  • CT colonography every 5 years 1, 2
  • Double-contrast barium enema every 5 years 1

For High-Risk Individuals

• Optical colonoscopy is the preferred screening method 1, 2
• Screening intervals should be more frequent:
  • Every 5 years for those with family history of colorectal cancer 1
  • More frequent intervals for those with inflammatory bowel disease or hereditary syndromes 1

Selection of Screening Method

• The choice of screening method should be based on:
  • Benefits and harms of the screening test 1
  • Availability of the screening test 1
  • Patient preferences and values 1, 2
• All positive results from non-colonoscopy screening tests must be followed up with timely colonoscopy 2
• The American College of Gastroenterology recommends colonoscopy as the preferred colorectal cancer prevention test 1

When to Stop Screening

• Screening should be discontinued in adults over age 75 years 1, 2
• Screening should be discontinued in adults with a life expectancy of less than 10 years 1, 3
• For adults aged 76-85 years, screening decisions should be individualized based on:
  • Overall health status 2, 3
  • Prior screening history 2, 3
  • Life expectancy 2, 3

Important Considerations and Pitfalls

• Quality of colonoscopy is critical for effective screening and should be monitored using quality indicators 2
• Inadequate bowel preparation can reduce colonoscopy effectiveness 2
• Failure to follow up positive stool-based tests with colonoscopy negates the benefit of screening 2
• Recent evidence suggests increasing colorectal cancer incidence in younger adults, which has led some organizations to recommend starting screening at age 45 4, 5, 6
• However, the American College of Physicians' most recent guidance (2023) recommends considering not screening asymptomatic average-risk adults between ages 45-49 years due to uncertainty around benefits and harms 7
• Implementing screening at age 45 would add approximately 19 million people to the screening-eligible population 4