From the Guidelines
If you have a family history of colon cancer, you should begin screening earlier than the general population, specifically at age 40 or 10 years before the youngest diagnosed family member, whichever comes first, with a preferred screening method of colonoscopy every 5 years, as recommended by the most recent guidelines 1. This approach is based on the understanding that family history significantly increases the risk of colorectal cancer due to its genetic components, with about 25-30% of cases showing familial clustering. The guidelines from the AGA clinical practice update on risk stratification for colorectal cancer screening and post-polypectomy surveillance: expert review 1 provide the most current and comprehensive recommendations for screening individuals with a positive family history of colon cancer.
Key Recommendations for Screening
- For individuals with a first-degree relative (parent, sibling, or child) diagnosed with colorectal cancer, screening should start at age 40 or 10 years before the youngest diagnosed family member, whichever comes first.
- The preferred screening method is a colonoscopy every 5 years.
- Alternative screening options include:
- Stool-based tests like the fecal immunochemical test (FIT) annually.
- Multi-target stool DNA test every 3 years.
- CT colonography every 5 years.
- For those with multiple affected relatives or relatives diagnosed before age 60, even more frequent screening may be recommended.
Importance of Lifestyle Modifications
In addition to screening, maintaining a healthy lifestyle is crucial to further reduce the risk of colon cancer. This includes:
- Eating a diet rich in fruits, vegetables, and fiber.
- Limiting red meat and processed foods.
- Exercising regularly.
- Avoiding tobacco.
- Limiting alcohol.
- Maintaining a healthy weight.
Evidence Base
The recommendations are supported by the most recent and highest quality studies, including the AGA clinical practice update 1, which emphasizes the importance of risk stratification for initiating CRC screening or surveillance based on age, family history, and other CRC predisposing conditions. Other guidelines, such as those from the US Multi-Society Task Force on Colorectal Cancer 1 and the National Comprehensive Cancer Network 1, also support early and regular screening for individuals with a family history of colon cancer. However, the AGA update 1 provides the most current and comprehensive guidance, making it the basis for these recommendations.
From the Research
Screening Strategies for Colon Cancer with Positive Family History
- Individuals with a positive family history of colorectal cancer (CRC) are at a higher risk, with a 2-fold or higher risk of CRC or advanced neoplasia 2
- Major US guidelines recommend starting CRC screening by age 40 for those with a first-degree relative (FDR) with CRC 2
- Barriers to screening include patient lack of knowledge on family and polyp history, provider limitations in collecting family history, and insufficient application of guidelines 2
Methods for Colon Cancer Screening
- Several methods are available for colon cancer screening, including fecal occult blood tests, flexible sigmoidoscopy, colonoscopy, CT colonography, capsule endoscopy, and double contrast barium enema 3
- A simple, inexpensive, noninvasive, and relatively sensitive screening test is needed to identify people at risk for developing advanced adenomas or colorectal cancer who would benefit from colonoscopy 3
- The combination of colonoscopy and immune fecal occult blood detection has garnered significant attention as a novel method for CRC screening 4
Effectiveness of Different Screening Strategies
- Colonoscopy and fecal occult blood tests, when combined, can improve screening accuracy and early detection rates, thereby facilitating early intervention and treatment 4
- A hierarchical screening strategy based on CRC risk assessment is feasible for screening for CRC in the population and can be used as an effective supplement to traditional colonoscopy and FIT screening programs 4
- CT colonography (CTC) is sensitive at a ≥6 mm threshold but specificity is lower and variable, and may adequately substitute for colonoscopy when the latter is undesirable 5
Emerging Technologies in Screening for Colorectal Cancer
- Emerging technologies include CT colonography, immunochemical fecal occult blood tests, and stool screening using molecular markers 6
- The American Cancer Society's (ACS) Colorectal Cancer Advisory Group has determined that at this time there is insufficient evidence to recommend these technologies for routine colorectal cancer screening, with the exception of immunochemical stool testing 6