Table of contents:
- What are tumor markers?
- What are they used for?
- Why is it performed?
- Preparation for tumor markers
- What does the test feel like?
- What the results of tumor markers mean
What are tumor markers?
Tumor markers are substances that are created by cancer cells or other cells in response to cancer or other pathologies. Although tumor markers can be produced by both healthy and cancerous cells, there are higher concentrations in cancerous cells.
These substances are usually found in blood, urine, stool, tumor tissue or other body tissues. They serve to help in the diagnosis of cancer but sometimes benign situations may cause an increase in the concentration of tumor markers or there may be cancer patients who do not have an elevated concentration of a tumor marker associated with cancer. Therefore, although they help to detect some cancers, they are not sufficient to diagnose the cancer itself, but must be combined with other tests such as biopsies.
In some cancer patients the concentration of a tumor marker can give information about the stage or extent of the tumor and the patient’s prognosis. However, various studies should be carried out periodically to check the progress of the disease.
In some patients with cancer the concentration of a tumor marker
can give information about the stage or extent of the tumor.
What are tumor markers used for?
Tumor marker tests have the following main objectives:
- Plan appropriate treatment
- To see if the cancer has spread to other tissues
- Predict the outcome of the disease
- To find out if the cancer has recurred
- To perform other screening tests
Why is it performed?
Tumor marker testing is performed for patients who have completed cancer treatment or are at very high risk for cancer, either because of family history or other reasons.
The type of test to be performed depends on the patient’s medical history and symptoms. Some of the most common tests are:
- CA-125 (cancer antigen 125) for ovarian cancer.
- CA 15-3 and CA 27-29 (cancer antigens 15-3 and 27-29) for breast cancer.
- PSA (prostate specific antigen) for prostate cancer.
- CEA (carcinoembryonic antigen) for lung cancer.
Preparation for the tumor marker test
Depending on the test, blood and urine samples are used and do not require any preparation other than fasting before the sample is taken.
In the case of a biopsy, the specialist will indicate the preparations to be followed. The biopsy consists of extracting a small sample of tissue by cutting or scraping the skin. If the tissue is inside the body, the necessary equipment is used to extract it.
What does the test feel like?
There are several ways to test for tumor markers. Blood tests are the most common, although it can also be done by urinalysis or by biopsy.
Meaning of abnormal results
Depending on the test performed to diagnose the type of cancer, abnormal results can:
- To help diagnose the type of cancer and the stage it is in
- To study if the results of the treatment are being fruitful
- To help in planning future treatment
- To show whether cancer cells are present after treatment