Tumors That Can Cause Elevated CEA Levels
All of the listed tumors (breast cancer, colorectal cancer, gastric cancer, and lung cancer) may cause elevated CEA levels. 1, 2, 3
CEA in Colorectal Cancer
- CEA is the marker of choice for monitoring metastatic colorectal cancer during systemic therapy 4
- Elevated preoperative CEA (≥5 ng/mL) correlates with poorer prognosis in colorectal cancer 4, 5
- Postoperative CEA monitoring is recommended every 3 months for patients with stage II or III colorectal cancer for at least 3 years after diagnosis 4, 5
- Despite its utility in monitoring, CEA has high specificity but low sensitivity for colorectal cancer, making it unsuitable for population screening 5
CEA in Breast Cancer
- CEA levels are elevated in 50-60% of patients with metastatic breast cancer 4
- CEA can be used for monitoring patients with metastatic breast cancer during active therapy, in conjunction with diagnostic imaging, history, and physical examination 4
- In breast cancer, CEA elevations may be found in 40-73% of patients presenting with disease in stages I-IV 3
- Approximately 80% of breast cancer patients will have a CEA elevation 3-10 months prior to clinical symptoms of recurrence 3
CEA in Lung Cancer
- 77% of patients with bronchogenic lung cancer have elevated preoperative CEA values 3
- In small cell carcinoma of the lung, CEA levels above 10 ng/ml correlate highly with metastatic disease 3
- Caution must be exercised when interpreting CEA levels in smokers, as smoking can cause an increase in CEA levels, making differentiation between benign and malignant conditions more difficult 3
CEA in Gastric Cancer
- Gastric malignancies demonstrate CEA level elevations in just over 50% of cases 3
- However, these elevations have not been found to be as clinically useful as in colorectal cancer 3
Other Factors Affecting CEA Levels
- Non-cancer related conditions can also affect CEA levels, including gastritis, peptic ulcer disease, diverticulitis, liver diseases, COPD, diabetes, and inflammatory states 4, 1, 6
- Certain medications, such as lithium, have been reported to cause reversible CEA elevation 6
- CEA levels are not influenced by sex, age, blood type, time of blood sampling, or family history of cancer 7
Clinical Application of CEA
- CEA is not recommended as a standalone diagnostic tool for any cancer type due to its limited sensitivity and specificity 1, 2
- Markedly increased CEA values (>25 ng/ml) are highly suggestive of metastatic cancer, particularly hepatic metastasis 7
- CEA levels typically correlate with tumor stage, degree of differentiation, and effectiveness of therapy across various cancer types 3
- Caution should be used when interpreting a rising CEA level during the first 4-6 weeks of a new therapy, as spurious early rises may occur 4