American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the recommended colonoscopy surveillance interval for patients at risk for Lynch syndrome?

1. Every year after age 30

2. Every 1 to 2 years starting at age 25

3. Every 3 to 5 years starting at age 20

4. Once a decade after age 40

The correct answer is: Every 1 to 2 years starting at age 25

The recommended colonoscopy surveillance interval for patients at risk for Lynch syndrome is every 1 to 2 years starting at age 25. Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer (HNPCC), is associated with an increased risk of colorectal cancer and certain other cancers. The early initiation of surveillance, starting at age 25, reflects the heightened risk these patients face for malignant transformation beginning at a younger age compared to the general population. Regular surveillance is critical in this group to ensure early detection and intervention. The recommended interval of 1 to 2 years aligns with guidelines suggesting that increased frequency is essential due to the rapid development of colorectal neoplasia in Lynch syndrome, providing a proactive approach to cancer prevention. Other proposed intervals, such as annual colonoscopy after age 30 or every 3 to 5 years starting at age 20, either do not begin early enough or do not sufficiently account for the aggressive nature of lesions that can arise in these patients. Lastly, recommending surveillance only once a decade after age 40 completely undermines the increased risk associated with Lynch syndrome. The established protocol aims to mitigate cancer risk through early detection, thereby improving patient outcomes.