When to Request CEA in Colorectal Cancer Patients
CEA should be measured preoperatively for staging and surgical planning, then monitored every 3 months for the first 3 years postoperatively and every 6-12 months during years 4-5 in patients with stage II or III colorectal cancer who are candidates for curative resection of metastases or systemic therapy. 1, 2
Preoperative CEA Testing
- Order CEA before surgery in all patients with newly diagnosed colorectal cancer to assist in staging and surgical planning 3, 2
- Preoperative CEA ≥5 ng/mL indicates worse prognosis regardless of tumor stage and should be documented as a baseline for postoperative monitoring 1, 3
Postoperative Surveillance Schedule
Years 1-3 After Curative Resection
- Measure CEA every 3 months for patients with stage II or III disease who would be candidates for surgical resection of metastases or systemic chemotherapy 1, 2
- This intensive monitoring detects 58-64% of all recurrences before other modalities and is the most cost-effective approach for identifying potentially resectable metastases 2, 4
Years 4-5 After Curative Resection
- Measure CEA every 6-12 months if the CEA was initially elevated preoperatively 1
- Continue monitoring only in patients who remain candidates for aggressive intervention 1
After 5 Years
- Routine CEA monitoring can be discontinued in most patients, though annual follow-up visits may continue 5
Monitoring During Active Treatment for Metastatic Disease
- Measure CEA at treatment initiation to establish a baseline 3, 2
- Monitor CEA every 1-3 months during active systemic therapy to assess treatment response 3, 2
- Two consecutive values above baseline strongly suggest disease progression, even without radiographic confirmation 3, 2
- Exercise caution when interpreting rising CEA during the first 4-6 weeks of new therapy (especially oxaliplatin), as spurious early rises may occur 3, 2
Clinical Context and Evidence Strength
The recommendation for intensive CEA monitoring is supported by multiple meta-analyses showing that surveillance incorporating CEA every 3-6 months is associated with significant mortality reduction (p=0.007) and enables earlier detection of asymptomatic resectable disease 1, 2. The FACS trial, the largest randomized study with 1202 patients, demonstrated that CEA monitoring increased the rate of curative-intent surgery for recurrence from 2.3% to 6.7% compared with minimal follow-up 6. However, this trial found no significant overall survival difference, suggesting any survival benefit is likely small (maximum 3.8%) 7, 6.
Important Caveats
- Do NOT use CEA for cancer screening in asymptomatic populations due to insufficient sensitivity and specificity 3, 2
- Do NOT initiate adjuvant or systemic therapy based on elevated CEA alone without radiographic or pathologic confirmation of disease 3, 2
- Always confirm elevated CEA with retesting before proceeding with extensive workup, as benign conditions (gastritis, peptic ulcer disease, liver disease, inflammatory bowel disease) can cause false elevations 3, 2
- CEA has higher sensitivity for detecting liver metastases (80%) compared to other sites of recurrence (46%), with a median lead time of 6-8 months before clinical detection 4, 8
When NOT to Order CEA
- Do not order CEA in patients who are not candidates for curative resection or systemic therapy due to comorbidities or poor functional status 1, 5
- Do not order CEA as a diagnostic test for suspected colorectal cancer—diagnosis requires histopathologic confirmation 1, 3
- Discontinue routine CEA monitoring if the patient's clinical status changes such that aggressive intervention would no longer be appropriate 1