What Are Tumor Marker Tests For Breast Cancer
Tumor markers are typically proteins that are produced by cancer cells, many of which can be found in the blood. Some examples of such tumor markers in breast cancer are:
- CA 15-3 and CA 27.29: CA 15-3 and CA 27.29 are two related markers that are made in higher amounts by breast cancer cells. As such, when theyre found in the blood, they can signal the presence of breast cancer.
- Carcinoembryonic antigen :CEA is a marker thats often used for colorectal cancer. However, it can also be applied to other types of cancer as well, including breast cancer.
- CA 125: CA 125 is a marker thats most often associated with ovarian cancer, but can also be a sign of breast cancer.
Additionally, sometimes parts of a tumor can break off and circulate in the blood. These circulating tumor cells can also be used as a tumor marker. High amounts of CTCs in the blood can mean that cancer is growing and spreading.
Tumor marker tests can be used by doctors to gauge the level of cancer activity in your body. This information may be useful to:
- evaluate how your cancer is responding to your current treatment
- see if your cancer has spread to other areas
- determine if a cancer thats been in remission has come back
Tumor marker tests can help to inform treatment decisions. For example, if a tumor marker is elevated, it may indicate that your current treatment isnt working. Your doctor may use this information to switch or adjust your treatment.
Mechanism Of Tumor Antigenesis
Normal proteins in the body are not antigenic because of self-tolerance, a process in which self-reacting cytotoxic T lymphocytes and autoantibody-producing B lymphocytes are culled “centrally” in primary lymphatic tissue and “peripherally” in secondary lymphatic tissue . Thus any protein that is not exposed to the immune system triggers an immune response. This may include normal proteins that are well sequestered from the immune system, proteins that are normally produced in extremely small quantities, proteins that are normally produced only in certain stages of development, or proteins whose structure is modified due to mutation.
Does Every Cancer Type Have A Tumor Marker
There is not a known tumor marker for all types of cancer. Also, tumor markers are not raised in all cases of the cancers they are used for, so they are not helpful for all patients. For example, carcinoembryonic antigen is a tumor marker used in colon cancer, yet only 70-80% of colon cancers make CEA. This means 20-30% of people with colon cancer will not have a high CEA level. Only 25% of early stage colon cancers have a higher than normal CEA. Because of this, CEA cannot always help find colon cancer in its early stages, when cure rates are best.
Tumor markers can be very helpful in watching your response to treatment and, in some cases, watching for the cancer to return. However, they need to be used along with your healthcare providers exam, any symptoms you are having, and radiology studies .
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What Is Being Tested
Cancer antigen 15-3 is a protein that is produced by normal breast cells. In many people with cancerous breast tumors, there is an increased production of CA 15-3 and the related cancer antigen 27.29. CA 15-3 does not cause cancer rather, it is shed by the tumor cells and enters the blood. This test measures CA 15-3 in the blood.
Since CA 15-3 can be measured in the blood, it is useful as a tumor marker to follow the course of the cancer. CA 15-3 is elevated in fewer than 50% of women with early localized, breast cancer or with a small tumor, but is elevated in about 80% of those with breast cancer that has spread . Because not all women with invasive breast cancer will have elevated CA 15-3, the test is not useful in all cases.
CA 15-3 is not recommended as a screening test to detect breast cancer in women because it is non-specific. It may also be elevated in healthy people and in individuals with other cancers such as colon, lung, pancreas, ovarian, or prostate malignancies or certain conditions such as cirrhosis, hepatitis, and benign breast disease.
Classification Of Tumor Antigens
Initially tumor antigens were broadly classified into two categories based on their pattern of expression: Tumor-Specific Antigens , which are present only on tumor cells and not on any other cell and Tumor-Associated Antigens , which are present on some tumor cells and also some normal cells.
This classification, however, is imperfect because many antigens thought to be tumor-specific turned out to be expressed on some normal cells as well. The modern classification of tumor antigens is based on their molecular structure and source.
Accordingly, they can be classified as
- Products of Mutated Oncogenes and Tumor Suppressor Genes
- Products of Other Mutated Genes
- Overexpressed or Aberrantly Expressed Cellular Proteins
- Tumor Antigens Produced by Oncogenic Viruses
- Oncofetal Antigens
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Guide To Tumor Markers Used In Cancer
This is a table of the most often used tumor markers, the cancers they can be found with, non-cancerous health issues that can cause them to be high, and the range of normal results.
In cases where the half-life is listed, this should be kept in mind when checking levels. For example, the PSA half-life is 2-3 days, so if the level were checked the day after surgical removal of the prostate, it would still be raised. If the level were checked a week later, the result should be zero, or very close to zero, if no prostate cells remain.
The Raised Level Of Tumor Markers Is Seen In The Following:
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What Does The Test Result Mean
In general, the higher the CA 15-3 level, the more advanced the breast cancer and the greater the amount of cancer present . CA 15-3 concentrations tend to increase as the cancer grows. In metastatic breast cancer, the highest levels of CA 15-3 often are seen when the cancer has spread to the bones and/or the liver.
Increasing concentrations of CA 15-3 over time may indicate that a person is not responding to treatment or that the cancer is recurring.
Normal CA 15-3 levels do not ensure that a person does not have localized or metastatic breast cancer. It may be too early in the disease process for elevated levels of CA 15-3 to be detected or the person may be one of the roughly 20% to 25% of individuals with advanced breast cancer whose tumors do not shed CA 15-3.
Mild to moderate elevations of CA 15-3 are seen in a variety of conditions, including cancer of the lung, pancreas, ovary, prostate, and colon as well as cirrhosis, hepatitis, and benign breast disorders and in a certain percentage of apparently healthy individuals. The CA 15-3 elevations seen in non-cancerous conditions tend to be stable over time.
When Is It Ordered
CA 15-3 may be ordered along with other tests when advanced breast cancer is first diagnosed to help determine cancer characteristics and treatment options. If beyond the cancer antigen 15-3 normal range, then it may be ordered periodically to monitor the effectiveness of treatment and to help watch for recurrence. CA 15-3 is usually not ordered when breast cancer is detected early, before it has spread , because levels will not be elevated in the majority of early cancers.
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Cost And Health Insurance
The cost of a CA 15-3 test can vary by location and generally runs between $50â$80 sometimes more. If you have to pay out of pocket or have high copayment costs, it helps to shop around for the best price. Even if you have insurance, check that the lab is an in-network provider otherwise, your claim may be denied.
The test doesn’t usually require preauthorization , but you may be limited as to how many tests you can take each year. Check your policy or call your health insurer for details.
If you are uninsured or struggling with treatment costs, ask your oncologist if there are any financial assistance programs you qualify for. You should also contact the Cancer Financial Assistance Coalition , a group of national organizations that provide financial help to people with cancer.
What Is The Significance Of The Ca 153 Blood Test Result
- Normal reference value of CA 15-3 for both males and females is < 30 U/mL . Increasing levels of CA 15-3 signify progression of breast cancer. About 80% of individuals with advanced breast cancer will show elevated levels of the protein CA 15-3
- Increased levels of CA 15-3 correlate with the spread of breast cancer despite treatment, or the return of the cancer after being successfully treated. The greater the size of the tumor or the more the spread of the breast cancer , the higher will be CA 15-3 levels
- Elevated levels of CA 15-3 may also be found in some other cases, such as liver disease , noncancerous breast lesion, and cancers of the lung, colon, pancreas, liver, ovary, cervix, endometrium, and prostate
- Low levels of CA 15-3 are related to localized type of breast tumor. If the levels start decreasing after initiation of treatment, it usually correlates with the regression of tumor due to effective therapy. Constant levels are associated with a stable disease
- It is very important to note that normal or low levels of CA 15-3 do not rule out advanced breast cancer, as 20-25% cases of advanced breast cancer will not show CA 15-3 elevation in blood. Likewise 10% of individuals with localized form of breast cancer will show elevated levels of CA 15-3
- Other lab tests and investigations are also performed along with CA 15-3 to determine the type of tumor and treatment options, once a diagnosis is confirmed
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How Is It Done
The CA 15-3 test is a blood test that can take place at a doctors office or in a hospital. A healthcare professional will use a needle to take a sample of blood from a vein in the arm.
They will then send the blood sample to a laboratory for testing. Depending on the laboratory, people may have to wait several days for the results.
I Have A Strong Family History Of Breast Cancer Shouldn’t I Be Screened For Ca 15
CA 15-3 is not recommended as a screening tool. It is not specific or sensitive enough to detect early breast cancer. Elevations in CA 15-3 may be due to other causes, and a normal value does not ensure that you do not have cancer. As a rule, it should only be used after breast cancer has been diagnosed.
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Why Might A Person Need This Test
A person may have a CA 15-3 test if they are currently undergoing treatment, or have had treatment, for invasive breast cancer.
The test can help a healthcare professional determine how well treatment is working or check for breast cancer recurrence. A CA 15-3 test can be a useful test to show whether a tumor is spreading or decreasing in response to treatment.
Doctors may also recommend a CA 15-3 test for people who have received a diagnosis of advanced breast cancer.
According to Lab Tests Online, CA 15-3 levels are elevated in about 80% of people with breast cancer that has spread to other areas of the body.
The test is not as useful for people with early stage or localized breast cancer, as less than 50% of these cases will involve elevated CA 15-3 levels.
Does A Person Need To Prepare For The Test
There is no need to prepare for a CA 15-3 test, but a person should make their doctor aware of any medications, supplements, or herbal remedies they are taking. A doctor may advise stopping taking some substances a few days before any lab tests.
For instance, according to the Food and Drug Administration , biotin supplements which some people take to promote the growth of hair and nails may interfere with certain lab tests.
The daily recommended biotin allowance for adults, which is 0.03 milligrams , is unlikely to cause any issues. However, the United Kingdoms National Health Service suggests that healthcare professionals wait 8 hours before collecting the sample if a person is taking more than 5 mg per day of biotin.
A normal test result for CA 15-3 levels is usually 30 units per milliliter or less.
Lab Tests Online notes that the levels of CA 15-3 generally increase in line with the advancement of breast cancer. Increased levels of CA 15-3 may, therefore, indicate that the cancer has spread to other areas of the body.
CA 15-3 levels that continue to increase over time may indicate that the:
- treatment is not working effectively
- cancer is continuing to spread
- cancer is recurring
In some cases, a person with normal CA 15-3 levels may still have breast cancer. In the early stages of breast cancer, CA 15-3 levels may not be high enough for a test to detect.
Also, about 2025% of people with advanced breast cancer have tumors that do not release CA 15-3.
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Can A Tumor Marker Be Used To Screen For Cancer
Ideally, markers could be used as a screening test for the general public. The goal of a screening test is to find cancer early, when it is the most treatable, and before it has had a chance to grow and spread. So far, the only tumor marker to gain some approval as a screening tool is the Prostate Specific Antigen for prostate cancer, though this has concerns as well.
The main worry with tumor markers is that they are not specific enough they have too many false positives. This means that the level is high when cancer is not present. This leads to costly tests that are not needed and causes the patient to be worried. The other concern is that the marker level is not high in early enough stages of the cancer, so the cancer cannot be found any earlier than when symptoms start to appear. Keep in mind that some substances used as tumor markers are normally made in the body, and a “normal” level is not always zero.
How Accurate Is The Test
Some laboratories use different methods to test for CA 15-3, which can produce varying results.
If a person needs multiple CA 15-3 tests over time, they should ask for the tests to take place in the same laboratory using the same method. This ensures that doctors can interpret and compare the results correctly.
It is important to note that not all doctors monitor the levels of CA 15-3, as other tumor markers are more sensitive. A 2018 study found that the tissue polypeptide-specific antigen was the best candidate for predicting the recurrence of breast cancer.
In addition, the CA 15-3 test is not always a reliable indicator of breast cancer, or recurring breast cancer. Generally, increasing levels of CA 15-3 indicate that breast cancer is advancing or recurring, while decreasing levels suggest that treatment is working effectively to reduce cancer. However, other factors, such as ethnicity and other medical conditions, can affect the levels of CA 15-3.
Research from 2020 that focused on females without breast cancer found that lower levels of CA 15-3 were present in those who:
- are perimenopausal
- have a history of uterine fibroids
- have taken birth control pills for an extended period
The researchers also found that elevated levels of CA 15-3 were present in Hispanic and Black females, as well as those with a history of endometriosis or lung cancer.
There are minimal risks to the CA 15-3 test, but people may experience the following at the needle insertion point:
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Clinical Definition Of Ca 153
Cancer antigen 15-3 is a protein produced by a variety of cells, particularly breast cancer cells. There is an increased production of CA 15-3 in persons with cancerous breast tumors however CA 15.3 test is not specific for breast cancer because levels are also increased in patients with gastric, colorectal, lung, pancreas, ovarian, uterine, and cervical cancers. CA 15.3 does not cause cancer.
What Is Ca 153 Blood Test
- CA 15-3 Test is a test to detect and measure the amount of CA 15-3 in blood
- CA 15-3 is a protein secreted by breast tissue and found in low levels in normal individuals. The presence of cancerous breast tissue increases the level of CA 15-3
- CA 15-3 Test is used to monitor breast cancer once it is diagnosed. It is also used to evaluate the effectiveness of treatment. However, this test is not used for screening or diagnosing breast cancer
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Pathophysiology Of Tumor Markers
Tumor markers: CA 15-3 use