American Board of Internal Medicine (ABIM) Certification Practice Exam

For how many years should patients at high risk for recurrence of colorectal cancer receive serial carcinoembryonic antigen measurements after resection?

1. 3 years

2. 5 years

3. 7 years

4. Indefinitely

The correct answer is: 5 years

Patients at high risk for recurrence of colorectal cancer should receive serial carcinoembryonic antigen (CEA) measurements for a period of 5 years after resection. This recommendation is grounded in clinical evidence that demonstrates the utility of CEA as a tumor marker that can help in the early detection of recurrence. Monitoring CEA levels during this period allows for timely intervention if a recurrence is identified, as early treatment can significantly improve outcomes. The guideline suggests that starting follow-up CEA measurements 3 to 4 months after surgery can help detect relapse as it may elevate before any clinical symptoms arise. Continuing these measurements during the first 5 years post-resection is crucial, as this timeframe encompasses the majority of recurrences. While some patients may experience recurrence beyond 5 years, the risk diminishes significantly after this period; hence, routine CEA measurement is typically not recommended indefinitely.