Please note: From 11^rd November 2013 , a new method of CEA analysis was introduced which will decrease results by upto 25%.

Carcinoembryonic antigen (CEA)

Reference range: <5µg/l

Carcinoembryonic antigen (CEA) is a tumour-associated, oncofetal antigen observed in embryonic and foetal tissues. The CEA family is a heterogeneous group of cell-surface glycoproteins.

Malignancies with elevated CEA:
CEA is raised in 60% patients with colorectal carcinoma, more commonly in those with advanced disease ( raised in 80-100% of those with hepatic metastases). CEA may be elevated in almost any advanced adenocarcinoma eg lung, breast, pancreas, liver, stomach, ovary, prostrate and in medullary carcinoma of thyroid.

Benign diseases which may have elevated CEA:
Lesser elevations occur in a number of non-malignant conditions eg hepatitis, cirrhosis, alcoholic liver disease, obstructive jaundice, pancreatic disease, inflammatory bowel disease, renal impairment, benign breast disease, collagen vascular disease, following treatment with 5-Fluorouracil and in some heavy smokers.

Screening
CEA is neither sufficiently specific nor sensitive enough to be used in screening for early colorectal carcinoma in asymptomatic individuals.

Main clinical applications:

1. In determining prognosis. Measurement of CEA pre-operatively in carcinoma of colon may predict risk of recurrence and may help identify patients who are candidates for adjuvant chemotherapy.
2. In surveillance following curative resection of colorectal cancer. Despite potentially curative surgery, 40 – 50% of patients with colorectal carcinoma develop recurrent or metastatic disease. Three monthly measurement of CEA may improve the detection of local recurrence at a resectable stage. A significant increase in CEA is an elevation of at least 30% greater than the previous value. This should be confirmed by a second sample taken within one month. Smaller increases of 15 – 20% maintained over at least three successive measurements may also prompt intervention. Serial measurements of CEA have a sensitivity of ~80% and a specificity of ~70% for detecting recurrence. Low concentrations of CEA do not necessarily exclude progression and in patients with clinical symptoms of recurrence additional tests eg colonoscopy are required regardless of CEA concentration.
3. In monitoring therapy in advanced colorectal cancer.
4. May be useful in monitoring treatment in other gastrointestinal malignancies.

New CEA reference interval 01/05/21, results unaffected.
AUH service users: new CEA units ug/L are equivalent to previous (ng/mL).

Back

Laboratory Services Home Page