Tumor Marker in Blood Tests: What Do They Mean

Certain types of cancers can produce excess proteins or cause specific patterns or changes in cell DNA. These are collectively referred to as tumor markers. Doctors use the presence of tumor markers in the blood to diagnose cancer, how fast it is growing, and the best course of treatment. Understanding tumor marker tests can help individuals better prepare for this blood test, which is crucial to cancer management.

This article explores tumor marker blood tests, including why they are required, how to prepare for them, how to interpret the test results, and more.

What is a Tumor Marker Test?

 
A tumor marker test is a type of blood test that checks the level of tumor markers in the blood stream. Tumor markers consist of:

• Certain proteins produced by cancer cells in significantly larger amounts than by normal cells.
• Mutations or a pattern of changes in cell DNA.

Some common cancer tumor markers in the blood include:

• AFP: It is used for the diagnosis of liver and testicular cancer.
• BRCA1 and BRCA2 Gene Mutations: These are commonly known as ovarian cancer tumor markers and are used for the diagnosis of breast and ovarian cancer.
• LDH: It is used for diagnosis, staging or treatment assessment of leukaemia, lymphoma, melanoma and germ cell tumors, among others.
• PSA: It is known as a prostate cancer tumor marker and is used for diagnosis or treatment assessment of prostate cancer.

When is the Tumor Marker Test Done?

Tumor marker tests are usually done after a cancer diagnosis. Doctors can prescribe a tumor marker blood test for patients:

1. Currently being treated for cancer.
2. Who have finished cancer treatment.
3. Who are at a high risk of certain types of cancers.

The type of tumor marker test prescribed depends upon health history, cancer diagnosis and presenting symptoms.

Why Is the Tumor Marker Test Required?

Apart from cancer diagnosis, tumor marker tests are also required (usually in conjunction with other tests) to:

1. Determine the stage of cancer, i.e. to find out whether cancer has spread to other parts of the body.
2. Predict the rate of growth, the chance of recovery, and the possibility of cancer recurrence.
3. Determine an effective treatment strategy for a specific type of cancer.
4. Assess the progress of cancer treatment.
5. Detect any remaining cancer after treatment.

How to Prepare for a Tumor Marker Test?

Tumor marker tests usually do not require any special preparation. Before scheduling the test, the doctor may ask about a patient’s medical history, including any history of hormone therapy or use of anti-inflammatory drugs.

Additionally, certain precautions can be recommended for better tumor markers accuracy. These include: 

• Avoiding strenuous exercise 24 hours before tumor marker tests, especially before a PSA test.
• Scheduling the test before certain medical procedures that can cause a temporary surge in tumor marker levels.

For women specifically, doctors can consider the menstrual cycle before scheduling ovarian cancer tumor markers, such as the CA-125 test, for better results.

How to Interpret Tumor Marker Test Results?

Doctors interpret the results of tumor marker tests by considering a variety of factors, including medical history and cancer diagnosis.

The results of the ovarian cancer tumor markers and prostate cancer tumor markers can be interpreted as follows:

1. PSA (Prostate Cancer Tumor Markers Test)

The results of the PSA test are expressed in PSA nanograms per millilitre of blood (ng/mL). The test limits are as follows:

• Below 4 ng/ml: Normal
• Above 4 ng/ml: Can indicate prostate cancer depending upon age and prostate size. A doctor can recommend a prostate biopsy.
• Rising PSA levels after treatment can signal cancer recurrence.

2. CA-125 (Ovarian Cancer Tumor Markers Test)

CA-125 levels are measured in units per millilitre (U/ml). The test limits are as follows:

• Between 0-35 U/ml: Normal
• Above 35 U/ml: Can indicate cancer or other conditions, including cancer recurrence. A doctor can recommend additional tests to confirm a diagnosis.

For patients diagnosed with ovarian cancer, a falling CA-125 level can indicate a good response to treatment, while a rising CA-125 level can indicate cancer growth or recurrence.

Tumor markers provide crucial diagnostic information to doctors regarding cancer, including rate of growth, treatment accuracy, and recurrence possibility. Doctors can also use tumor marker tests to plan an effective treatment strategy.

With many types of cancer, especially ovarian cancer, early detection usually leads to a favourable prognosis. Upon noticing signs of ovarian cancer, it is a good idea to consult a doctor and book a CA 125 test at Dr Lal PathLabs.

Download the Dr Lal PathLabs app for screening today!

FAQs

1. What cancers can be detected by tumor marker tests?

Tumor markers help detect prostate, ovarian, liver, testicular, and gastrointestinal cancers when used in conjunction with imaging and clinical evaluation.

2. Can tumor markers be high without having cancer?

Yes, tumor markers can rise due to infections, inflammation, or benign conditions and must be evaluated in conjunction with other clinical findings.