Tumour markers

Keywords: CA 125, CA 19.9, CA 15.3

Specimen:

5 mL blood in plain tube.

Method:

Immunoassay.

Reference Interval:

Depends on marker and method.

Application:

The tests should generally not be used as either screening or diagnostic tests for malignancy, as these markers may be elevated by non-malignant diseases. Also of note the below tumour markers may be elevated by a variety of malignancies.

They may be used to monitor histologically diagnosed patients with a malignancy that has been shown to produce the marker.

CA 125 is a marker used for serous carcinoma, especially carcinoma of the ovary, but elevations are also seen in peritoneal disease of any cause.

CA 19.9 is a marker used for gastrointestinal malignancy, especially carcinoma of the pancreas.

CA 15.3 is a marker used for breat malignancy.

Other tumour markers are available but generally have only limited utility in monitoring disease.

See also: Carcinoembryonic Ag,

Alpha-fetoprotein,

Neuron-specific enolase,

Prostate specific antigen,

and Beta HCG quantitation.

Interpretation:

Persistence of an increased level after treatment indicates a significant amount of residual tumour.

Decrease to a normal level after treatment may mean eradication of the tumour or persistence of only small amounts of tumour; subsequent elevation indicates regrowth of the tumour.

Lesser elevations may be found in some non-malignant conditions.

Reference:

Perkins GL et al. Am Fam Physician. 2003; 68(6): 1075-1082.

Duffy MJ et al. Eur J Cancer. 2003; 39(6): 718-727.