American Board of Internal Medicine (ABIM) Certification Practice Exam

At what age should colorectal cancer screening via colonoscopy begin for patients with Lynch syndrome?

1. Between 15 and 20 years

2. 20 to 25 years

3. 25 to 30 years

4. Before the age of 15

The correct answer is: 20 to 25 years

For patients with Lynch syndrome, which is a hereditary condition increasing the risk of colorectal and other types of cancer, screening for colorectal cancer is critical. The recommended starting age for colorectal cancer screening via colonoscopy for individuals with Lynch syndrome is between 20 to 25 years. This recommendation is based on studies showing that individuals with Lynch syndrome have a significantly increased risk of developing colorectal cancer at a younger age compared to the general population, necessitating earlier and more frequent surveillance. Starting the screening at 20 to 25 years allows for earlier detection of any precancerous lesions or cancers, which is vital for improving patient outcomes. The rationale behind this recommendation is also tied to the specific increased lifetime risk of colorectal cancer associated with Lynch syndrome, which can reach up to 80% in some cases. Options proposing a starting age before 20 or even under 15 do not align with established guidelines and would likely lead to missed diagnoses. Conversely, beginning screening after 25 is too late given the heightened risk associated with this genetic condition. Thus, the option of initiating screening between 20 to 25 years is the most appropriate and aligns with current clinical guidelines for monitoring patients with Lynch syndrome.