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CEA (Carcinoembryonic Antigen)

CEA — tumor marker used for treatment monitoring in colorectal and lung cancers.

Carcinoembryonic antigen test used in monitoring treatment response and recurrence of certain solid tumors, primarily colorectal cancer. Not used for screening.

Indication

  • Treatment follow-up and recurrence monitoring in colorectal (large bowel) cancer
  • Assessment of treatment response in lung cancer
  • Follow-up in breast, gastric, and pancreatic cancers (per clinical decision)
  • Postoperative residual disease assessment
  • Monitoring chemotherapy efficacy
  • Supportive testing in suspected metastasis

Preparation

  • Special fasting is not required; evaluated according to the routine follow-up plan
  • Smoking status should be reported (values may be slightly elevated in smokers)
  • Bringing current treatment information and prior results

How it's performed

  1. A venous blood sample is drawn from the arm
  2. Measurement is performed on serum by immunoassay
  3. Result is reported in ng/mL
  4. The trend (change over time) is more informative than a single measurement

Post-procedure

  • Repeat measurement at defined intervals during the treatment process
  • Results are interpreted together with imaging and clinical findings
  • Rising values may require further investigation
  • Careful interpretation in conditions such as smoking and liver disease

Risks

  • Minor bruising or tenderness related to blood draw
  • False elevation in smokers and in COPD, liver disease, and inflammatory bowel disease
  • Values may be normal in early-stage cancers (false negatives)
  • Insufficient on its own for diagnosis or screening

FAQ

My CEA is elevated — do I have cancer?

Not necessarily. It can also rise in benign conditions such as smoking, liver diseases, and chronic lung disease. Clinical evaluation is essential.

Can it be used for colorectal cancer screening?

No. Colonoscopy and stool occult blood tests are used for screening. CEA is preferred for monitoring in patients with a confirmed diagnosis.

If I smoke, is my result reliable?

Smoking can mildly elevate CEA. The physician takes smoking status into account when interpreting the result.