Tumor Markers: What are they?

Tumor markers are substances that can be detected in high-than-normal amounts in the blood, urine, or body tissues of some patients with certain types of cancer. A tumor marker may be made by a tumor itself or by the body in response to the tumor.

Cancer Cells. Photo via http://www.pathguy.com

Although tumor markers are typically imperfect as screening tests to detect occult (hidden) cancers, once a particular tumor has been found the marker may be used as an indicator for monitoring the success or failure of treatment. The tumor marker level may also reflect the extent or the stage of the disease, indicate how quickly the cancer is likely to progress and so help determine the prognosis.

CA 27-29: A marker that is found in the blood of most breast cancer patients. CA 27-29 levels may be used in conjunction with other procedures (such as mammograms and measurements of other tumor marker levels) to check for recurrence in women previously treated for stage II and stage III breast cancer. CA 27-29 levels can also be elevated by cancers of the colon, stomach, kidney, lung, ovary, pancreas, uterus, and liver.

CA 125: is a protein that is a so-called biomarker, which is a substance that is found in greater concentration in tumor cells that in other cells of the body. In particular, CA 125 is present in greater concentration in ovarian cancer cells that in other cells.

CEA [Carcinoembryonic Antigen] is a protein found in many types of cells but associated with tumors in the body and fetus growth. CEA is tested in blood. The main use of CEA is as a tumor marker, especially with intestinal cancer. The most common cancers that elevate CEA are in the colon and rectum. Others include:

• Pancreas
• Stomach
• Lung
• Breast
• Certain types of Thyroid cancer

CEA levels over 20 ng/ml are associated with cancer which has already metastasized (spread). A riding CEA level indicates progression or recurrence of the cancer. CEA is useful in monitoring the treatment of CEA-rich tumors; if the CEA is high before treatment, it should fall to normal [<5.0 ng/ml] after successful therapy.

It would  be wise for the Caregiver to become familiar with the particular marker associated with the type of cancer diagnosed for the patient. You can then participate in following or “tracking” the effects of treatment, or conversely the growth of cancer reflected in the blood stream. These are not measures, but rather an indicator of the directions taken by the disease.

You can trace the general progression or containment of your loved one’s cancer by following these markers or indicators.

[See column number 6 of Lab Results, Exhibit 2b.] 

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