Malignancies Associated with Elevated CEA Levels
CEA is elevated in a wide range of epithelial malignancies, with colorectal cancer being the most clinically relevant, but significant elevations also occur in pancreatic, gastric, lung, breast, medullary thyroid, and gynecologic cancers. 1, 2, 3
Primary Malignancies with Elevated CEA
Gastrointestinal Cancers
Colorectal Cancer:
- CEA is the marker of choice for monitoring metastatic colorectal cancer during systemic therapy 1, 2
- Elevated in the majority of patients with advanced disease, with preoperative levels ≥5 ng/mL correlating with poorer prognosis 1, 4
- Has high specificity but low sensitivity, making it unsuitable for screening 2, 4
Pancreatic Cancer:
- CEA levels are elevated in just over 50% of pancreatic malignancies 3
- Patients with pancreatic cancer can have among the highest median CEA levels across all cancer types 5
Gastric Cancer:
- Elevated CEA found in approximately 50% of gastric malignancies 3
- CA 19-9 does not discriminate between cholangiocarcinoma, pancreatic, or gastric malignancy 1
Cholangiocarcinoma:
- CEA is raised in approximately 30% of patients with cholangiocarcinoma 1
- Can also be elevated in inflammatory bowel disease and biliary obstruction, limiting specificity 1
Thoracic Malignancies
Lung Cancer:
- 77% of patients with bronchogenic lung cancer have elevated preoperative CEA values 3
- In small cell carcinoma, CEA levels above 10 ng/mL correlate highly with metastatic disease, while values less than 2.5 ng/mL correlate with localized disease 3
- Lung cancer patients can have among the highest median CEA levels across malignancies 5
- Important caveat: Cigarette smoking independently causes CEA elevation, making differentiation between benign and malignant conditions more difficult 3
Breast Cancer
- CEA levels are elevated in 50-60% of patients with metastatic breast cancer 2
- CEA elevations may be found in 40-73% of patients presenting with disease in stages I-IV 3
- 80% of patients will have CEA elevation 3-10 months prior to clinical symptoms of recurrence 3
- Can be used for monitoring patients with metastatic breast cancer during active therapy, in conjunction with diagnostic imaging 2
Endocrine Malignancies
Medullary Thyroid Carcinoma (MTC):
- MTC is a critical but often overlooked cause of elevated CEA 6, 7
- Key clinical pitfall: In patients with resected colorectal cancer and persistently rising CEA without evidence of recurrence on imaging, MTC should be considered as a metachronous malignancy 6, 7
- Fine needle aspiration has a higher false negative rate in detecting MTC than other forms of thyroid cancer, so repeat FNAC and measurement of serum calcitonin are recommended for early detection 7
Gynecologic Malignancies
- Epithelial neoplasms of the female reproductive tract (cervix, uterus, and ovary) produce CEA in 47-75% of cases 3
- CEA levels may correlate with stage of disease at diagnosis and level of cellular differentiation 3
Clinical Interpretation Considerations
Non-Malignant Causes:
- Non-cancer conditions can elevate CEA, including gastritis, peptic ulcer disease, diverticulitis, liver diseases, COPD, diabetes, and inflammatory states 2, 4
- Chronic obstructive pulmonary disease and uremia can produce among the highest median CEA levels, even exceeding some malignancies 5
- Aging itself is associated with increased CEA levels, with healthy individuals older than 65 years having higher median levels than younger individuals 5
Monitoring During Treatment:
- CEA levels may be transiently elevated during the first 4-6 weeks of chemotherapy, particularly after oxaliplatin, and should be interpreted with caution during this period 1, 2
- Persistently rising CEA values above baseline strongly suggest disease progression even without radiographic confirmation 1, 2
Diagnostic Approach: