Tumor / Cancer screening tests

This category includes tumor markers, sometimes called cancer markers, in the blood, urine, or body tissues. Tumor markers are substances made by cancer cells or by normal cells in response to cancer in the body. Some tumor markers are specific to one type of cancer. Others can be found in several types of cancers.

Tumor marker tests are most often used to:

- Plan your treatment. If tumor marker levels go down, it usually means the treatment is working.
- Help find out if a cancer has spread to other tissues
- Help predict the likely outcome or course of your disease
- Check to see if your cancer has come back after successful treatment
- Screen people at high risk for cancer.

Risk factors can include family history and previous diagnosis of another type of cancer.

Cancer screening tests also aim to find cancer early, before it causes symptoms and when it may be easier to treat successfully.

Effective screening tests are those that:

- Find cancer early

- Reduce the chance that someone who is screened regularly will die from the cancer

- Have more potential benefits than harms. (Possible harms of screening tests include bleeding or other physical damage, inaccurate test results, and overdiagnosis—the diagnosis of cancers that would not have caused problems and did not need treatment.)

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Note: Can tumor markers be used in cancer screening? 

Because tumor markers can be used to predict the response of a tumor to treatment and for prognosis, researchers have hoped that they might also be useful in screening tests that aim to detect cancer early, before there are any symptoms.

However, although tumor markers are extremely useful for determining whether a tumor is responding to treatment or assessing whether it has recurred, no tumor marker identified to date is sufficiently sensitive (that is, able to correctly identify people who have the disease) or specific (that is, able to correctly identify people who do not have the disease) to screen for cancer. 

For example, until recently, the prostate-specific antigen (PSA) test, which measures the level of PSA in the blood, was used routinely to screen men for prostate cancer. However, an increased PSA level can be caused by benign prostate conditions as well as by prostate cancer, and most men with an elevated PSA level do not have prostate cancer. Because results from clinical trials showed that PSA testing leads at best to only a small reduction in the number of prostate cancer deaths and can lead to overdiagnosis and overtreatment, the PSA test is no longer recommended for routine screening. Now it is often used to monitor men with a history of prostate cancer to see if their cancer has come back. See the PSA Test fact sheet for more information.

Alpha Fetoprotein (AFP)

Optimal range: 0 - 8.3 U/mL

AFP stands for alpha-fetoprotein. It is a protein made in the liver of a developing baby. AFP levels are usually high when a baby is born, but fall to very low levels by the age of 1. An AFP tumor marker test is a blood test that measures the levels of AFP in adults. Tumor markers are substances made by cancer cells or by normal cells in response to cancer in the body.

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Carcinoembryonic Antigen (CEA)

Optimal range: 0 - 3.9 ng/mL

Carcinoembryonic antigen (CEA) is a glycoprotein normally found in embryonic entodermal epithelium.

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CD19

Optimal range: 200 - 2100 U/L

The CD19 antigen (aka B-lymphocyte antigen CD19 or Cluster of Differentiation 19) plays an important role in clinical oncology. It’s a protein found on the surface of B-cells, a type of white blood cell.

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Prostate Specific Antigen (PSA)

Optimal range: 0 - 4 ng/mL

The Prostate-specific antigen (PSA) test measures the amount of prostate specific antigen proteins made by the prostate gland and prostate cancers. It is used as a screen for prostate cancer, or a way to monitor progress of prostate cancer patients.

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PSA, % Free

Optimal range: 25 - 50 %

The free prostate-specific antigen test, known as the free PSA test, is used to help detect signs of prostate cancer. The test measures the level of unbound prostate-specific antigen in the blood, which can help doctors to diagnose issues like inflammation of the prostate or cancer.

Free PSA tests are often used alongside other PSA tests to confirm a diagnosis or test results. Free PSA tests can also be used instead of a biopsy if the doctor suspects prostate cancer, but a biopsy may still be needed.

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