From the Guidelines
Individuals at high risk for colon cancer should begin screening at age 40 or 10 years before the youngest affected relative's diagnosis, whichever comes first, as recommended by the latest guidelines 1. When it comes to colon cancer screening for high-risk individuals, several factors need to be considered, including family history, age, and predisposing hereditary CRC syndromes.
- High-risk groups include those with a family history of colorectal cancer or advanced adenomas, personal history of inflammatory bowel disease, genetic syndromes like Lynch syndrome or familial adenomatous polyposis, or previous radiation to the abdomen.
- The preferred screening method is colonoscopy every 5 years for most high-risk patients, though those with certain genetic syndromes may need more frequent screening (every 1-2 years) 1.
- Alternative screening options include annual fecal immunochemical testing (FIT) or stool DNA testing every 3 years, but these are less optimal for high-risk individuals. Key considerations for screening include:
- Age: screening is recommended for average-risk adults starting at age 45 years, but high-risk individuals should start earlier, at age 40 or 10 years before the youngest affected relative's diagnosis 1.
- Family history: individuals with a family history of CRC should be screened 10 years before the age at diagnosis of the youngest affected relative or age 40 years with colonoscopy 1.
- Prior screening: risk stratification for initiating CRC screening or surveillance should be based on prior screening, among other factors 1. Early and more frequent screening is crucial because high-risk individuals can develop cancer at younger ages and may have more aggressive disease progression, as noted in the latest clinical practice update on risk stratification for colorectal cancer screening and post-polypectomy surveillance 1.
From the Research
Colon Cancer Screening for High-Risk Individuals
- The American College of Medical Genetics and Genomics has developed technical standards and guidelines for genetic testing for inherited colorectal cancer, including Lynch syndrome, familial adenomatous polyposis, and MYH-associated polyposis 2.
- Individuals with a family history of colorectal cancer are at higher risk and may need to start screening earlier, with some studies suggesting that they may need to start screening 3-29 years earlier than the general population 3.
- The US Multi-Society Task Force on Colorectal Cancer has developed guidelines for the genetic evaluation and management of Lynch syndrome, including a colorectal cancer risk assessment tool and algorithms for genetic evaluation of affected and at-risk family members 4.
Screening Recommendations
- The starting age for colon cancer screening may need to be adjusted based on an individual's family history, with some studies suggesting that screening should start at age 45 instead of 50 5.
- Individuals with Lynch syndrome are at increased risk for colorectal cancer and other cancers, such as gynecological cancers, and may need more frequent screening and surveillance 6, 2.
- Genetic testing can help identify individuals at risk for inherited colorectal cancer and inform screening and management decisions 2, 4.
Considerations for Screening
- Lowering the starting age for colon cancer screening to 45 may lead to a reduction in colorectal cancer incidence and mortality, but may also require additional healthcare resources 5.
- A comprehensive family history is important for identifying individuals at risk for inherited colorectal cancer and informing screening and management decisions 6, 4.
- Counseling is an important component of the management of individuals with Lynch syndrome and other inherited colorectal cancer syndromes 6, 4.