From the Guidelines
If you have a first-degree relative, like an uncle, who had colon cancer, you should start colonoscopy screening at age 40 or 10 years before the age your relative was diagnosed, whichever comes first, and repeat every 5 years 1. This recommendation is based on the most recent guidelines from the American Gastroenterological Association, which suggest that adults with an increased risk of CRC based on a family history of CRC should begin CRC screening at age 40 y or 10 y before earliest diagnosis of CRC with colonoscopy every 5 to 10 y 1. The frequency of screening may vary depending on additional family history or genetic factors, such as multiple family members with colorectal cancer or hereditary syndromes like Lynch syndrome 1. Some key points to consider when determining the screening schedule include:
- The age at which your relative was diagnosed with colon cancer
- The presence of other family members with colorectal cancer or advanced adenomas
- Your personal medical history and lifestyle factors
- The presence of other conditions that may influence the recommended screening schedule It's essential to discuss your specific family history with your healthcare provider, as they may recommend genetic counseling to determine if you have inherited a genetic mutation that increases your risk 1. Your doctor will consider all these factors to determine the best screening schedule for you, which may include more frequent screenings (every 1-2 years) if you have a higher risk of developing colorectal cancer 1.
From the Research
Colonoscopy Screening Frequency
If an uncle had colon cancer, the frequency of colonoscopy screening for family members is as follows:
- Persons with a family history of CRC or a documented advanced adenoma in a first-degree relative age <60 years or 2 first-degree relatives with these findings at any age are recommended to undergo screening by colonoscopy every 5 years, beginning 10 years before the age at diagnosis of the youngest affected relative or age 40, whichever is earlier 2.
- Persons with a single first-degree relative diagnosed at ≥60 years with CRC or an advanced adenoma can be offered average-risk screening options beginning at age 40 years, which may include colonoscopy every 10 years 2.
Screening Tests and Recommendations
The U.S. Multi-Society Task Force on Colorectal Cancer recommends the following screening tests:
- Colonoscopy every 10 years as a first-tier test 2.
- Annual fecal immunochemical test (FIT) as a first-tier test 2.
- CT colonography every 5 years, FIT-fecal DNA test every 3 years, and flexible sigmoidoscopy every 5 to 10 years as second-tier tests 2.
Comparison of Screening Tests
Studies have compared the effectiveness of different screening tests, including:
- Flexible sigmoidoscopy versus fecal occult blood testing (FOBT) for colorectal cancer screening in asymptomatic individuals, which found that both tests reduce colorectal cancer mortality, but the comparative effectiveness of these tests on colorectal cancer mortality has never been evaluated 3.
- Fecal occult blood testing (FOBT) for colorectal cancer screening, which has been shown to reduce substantially colorectal cancer mortality and incidence 4.
- Colonoscopy, sigmoidoscopy, and FOBT for colorectal cancer screening in asymptomatic adults, which found that colonoscopy can detect neoplastic lesions undetectable by FOBT and sigmoidoscopy 5.