CEA

Carcinoembryonic Antigen

Tumormarker

Zuletzt geprüft: 7. April 2026. Quellenansatz: Standardkontext zur Laborinterpretation, allgemeine medizinische Referenzmaterialien sowie öffentliche Gesundheits- oder klinische Leitlinien, sofern relevant.

Was ist Carcinoembryonic Antigen?

Carcinoembryonic antigen (CEA) is a glycoprotein involved in cell adhesion that was first identified in 1965 in extracts of human colon carcinoma tissue and fetal gut. It belongs to the immunoglobulin superfamily and is anchored to the cell membrane via a glycosylphosphatidylinositol (GPI) linkage. During fetal development, CEA is produced in gastrointestinal tissue and its production normally decreases after birth, with low levels present in the blood of healthy adults.

CEA is the most widely used tumor marker for colorectal cancer (CRC). Its primary clinical utility lies in monitoring for recurrence after curative surgery, assessing response to chemotherapy in metastatic disease, and aiding prognostic stratification. Elevated preoperative CEA is an independent adverse prognostic factor in colorectal cancer. CEA is not suitable for screening because it lacks sensitivity for early-stage disease and is elevated in many benign conditions and other malignancies. Smoking is a well-established cause of mildly elevated CEA in the absence of malignancy.

Warum der Wert wichtig ist

CEA is the standard serum marker for colorectal cancer surveillance. A rising CEA after curative surgery is often the earliest sign of recurrence, preceding imaging findings by several months, and may prompt earlier intervention with potentially curative salvage surgery. In metastatic colorectal cancer, serial CEA tracks chemotherapy response. Preoperative CEA >5 ng/mL is an adverse prognostic factor. While CEA is elevated in multiple cancer types, its clinical validation is strongest for colorectal cancer.

Normale Referenzbereiche

GruppeBereichEinheit
Non-smokers0–3.0ng/mL
Smokers0–5.0ng/mL

Referenzbereiche können je nach Labor variieren. Vergleichen Sie Ihre Ergebnisse immer mit den Bereichen Ihres Testlabors.

Was hohe CEA-Werte bedeuten

Häufige Ursachen

  • Colorectal cancer (most validated use)
  • Smoking (mild elevations up to 5–10 ng/mL)
  • Inflammatory bowel disease (Crohn's, ulcerative colitis)
  • Pancreatitis and pancreatic cancer
  • Gastric, breast, and lung cancers
  • Liver cirrhosis and hepatitis
  • Peptic ulcer disease
  • Hypothyroidism
  • Cholecystitis

Mögliche Symptome

  • Change in bowel habits
  • Rectal bleeding or blood in stool
  • Unexplained weight loss
  • Abdominal pain or cramping
  • Fatigue and weakness
  • Iron deficiency anemia

Was zu tun ist: In known colorectal cancer patients, a rising CEA warrants imaging (CT of chest, abdomen, pelvis) to identify the site of recurrence. If CEA rises postoperatively but imaging is negative, PET/CT or colonoscopy may be considered. For initial elevations without a cancer diagnosis, investigate benign causes (smoking, inflammatory conditions, liver disease) and consider repeat testing in 4–8 weeks. Persistent unexplained elevations should prompt further investigation including colonoscopy.

Was niedrige CEA-Werte bedeuten

Häufige Ursachen

  • Normal physiological state
  • Successful surgical resection or treatment of cancer

Mögliche Symptome

  • No symptoms associated with low CEA

Was zu tun ist: Low CEA is normal and expected. After colorectal cancer surgery, normalization of CEA (within 4–6 weeks postoperatively) is a favorable prognostic indicator. However, some colorectal cancers do not produce CEA, so a normal level does not guarantee the absence of disease. Continued surveillance with imaging and colonoscopy is still necessary.

Wann wird ein CEA-Test empfohlen?

  • Preoperative staging and prognosis in colorectal cancer
  • Post-surgical surveillance for colorectal cancer recurrence (every 3–6 months for 2 years, then every 6 months for 3 more years)
  • Monitoring response to chemotherapy in metastatic colorectal cancer
  • Evaluating unexplained liver metastases of unknown primary

Häufig gestellte Fragen

Not necessarily. CEA can be elevated in many benign conditions including smoking, inflammatory bowel disease, liver disease, and hypothyroidism. Mild elevations (3–10 ng/mL) are more often benign, while very high levels (>20 ng/mL) are more concerning for malignancy. Clinical context, imaging, and often colonoscopy are needed to determine the cause.
ASCO and NCCN guidelines recommend measuring CEA every 3–6 months for the first 2 years after surgery, then every 6 months for years 3–5. CEA monitoring is recommended for stage II and III patients who would be candidates for further treatment if recurrence is detected.
No. CEA is not sensitive enough for early-stage detection—it is elevated in only about 30–40% of stage I–II colorectal cancers. Colonoscopy remains the gold standard for early detection and screening. CEA is most useful for recurrence surveillance and monitoring advanced disease.

Verwandte Biomarker

CA 19-9Cancer Antigen 19-9CA-125Cancer Antigen 125

Quellen- und Prüfungsansatz

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Medizinischer Hinweis: Diese Informationen dienen nur Bildungszwecken und ersetzen keine professionelle medizinische Beratung, Diagnose oder Behandlung. Referenzbereiche können zwischen Laboren variieren. Besprechen Sie die Interpretation Ihrer konkreten Testergebnisse immer mit Ihrer medizinischen Fachperson.

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