Carcinoembryonic Antigen (CEA)

The Carcinoembryonic Antigen (CEA) test measures the level of CEA, a protein that is normally present at very low levels in healthy adults. CEA is considered a tumor marker, and elevated levels may be associated with certain cancers, especially colorectal cancer. It is commonly used to monitor treatment response and detect cancer recurrence.

1. What Is CEA?

• CEA is a glycoprotein involved in cell adhesion and is normally produced during fetal development.

• In healthy adults, CEA levels are usually very low or undetectable.

• Some cancers may produce large amounts of CEA, making it useful for cancer detection and monitoring.

2. Why Is the CEA Test Performed?

This test is used to:

• Monitor colorectal cancer after diagnosis and during treatment.

• Detect cancer recurrence after surgery or chemotherapy.

• Sometimes used to assess other cancers (e.g., lung, breast, pancreatic, or stomach).

• Occasionally ordered when cancer is suspected based on symptoms and imaging studies.

3. CEA Reference Ranges

• Non-smokers: < 3.0 ng/mL

• Smokers: < 5.0 ng/mL

• Levels above the normal range may suggest cancer or other conditions, but CEA is not cancer-specific.

4. How to Interpret CEA Results

🔹 Elevated CEA:

• May indicate cancer of the colon, rectum, or other organs (especially if levels continue to rise).

• May also occur in non-cancerous conditions like liver disease, inflammatory bowel disease, or smoking.

🔹 Declining CEA:

• Suggests a positive response to treatment (e.g., surgery or chemotherapy).

🔹 Rising CEA after treatment:

• May signal recurrence or spread (metastasis) of cancer.

5. What Can Affect CEA Levels?

• Smoking (can cause moderately elevated levels)

• Liver disease (e.g., cirrhosis, hepatitis)

• Infections and inflammatory conditions (e.g., pancreatitis, IBD)

• Certain benign tumors

6. How Is the Test Performed?

• A blood sample is taken from a vein, typically requiring no special preparation.

• Serial measurements may be taken over time to monitor trends.

7. When to See a Doctor

🚨 Contact your healthcare provider if you:

• Have a known cancer diagnosis and rising CEA levels.

• Are being monitored for cancer recurrence after treatment.

• Have persistent symptoms (e.g., weight loss, abdominal pain, blood in stool) along with elevated CEA.

🔹 Key Takeaways

✅ CEA is a tumor marker primarily used for monitoring colorectal and other cancers.

✅ It is not used for cancer screening due to limited specificity and sensitivity.

✅ Rising or falling levels help guide treatment decisions and follow-up care.