8 Types of Cancer Marker Tests Explained
5 mins read
A cancer marker test measures substances in the blood, urine, or other body fluids that may provide information about certain cancers, but it is not usually used on its own to diagnose cancer.
Different tumour markers are associated with different types of cancer, and each test has specific uses, limitations, and clinical applications.
Healthcare providers often use cancer marker tests alongside imaging studies, physical examinations, biopsies, and other laboratory investigations.
Not all cancers produce tumour markers, and elevated marker levels do not always indicate cancer, as some non-cancerous conditions can also affect results.
Cancer diagnosis often involves several different tests working together to build a complete picture of a person's health. Among these investigations are tumour marker tests, which measure specific substances that may be produced by cancer cells or by the body in response to cancer.
A cancer marker test helps healthcare providers assess certain cancers, monitor treatment response, evaluate disease recurrence, or support further investigations, but it is generally not sufficient on its own to diagnose cancer [1].
Understanding what these tests measure—and what they cannot tell you—is important if your healthcare provider recommends one as part of your evaluation. Below are eight commonly used cancer marker tests and how they fit into modern cancer care.
A cancer marker test detects substances known as tumour markers in blood, urine, or other body fluids. These markers may include proteins, hormones, enzymes, or other molecules associated with certain cancers.
While tumour markers can provide valuable clinical information, they are not perfect indicators. Some people with cancer have normal tumour marker levels, while others without cancer may have elevated levels due to benign conditions such as inflammation, infections, or liver disease [2].
For this reason, healthcare providers interpret the results alongside your symptoms, medical history, imaging findings, and, when necessary, tissue biopsy results.
PSA is one of the most widely recognised tumour markers. It is a protein produced by the prostate gland and is measured through a blood test. Healthcare providers may use PSA to:
However, elevated PSA levels are not specific to cancer. Benign prostate enlargement, prostatitis, and even recent urinary procedures may also increase PSA levels [3].
CA-125 is commonly associated with ovarian cancer. It may be used to:
CA-125 is not recommended as a standalone screening test for ovarian cancer in the general population because levels may also increase due to [4]:
A tumour marker test measuring CA-125 is therefore interpreted within the context of other clinical findings.
CEA is associated with several types of cancer, including:
Healthcare providers most commonly use CEA to monitor treatment effectiveness and assess for recurrence after therapy.
Smoking and several non-cancerous medical conditions may also elevate CEA levels, limiting its usefulness as a screening tool.
Tumour Marker | Common Clinical Uses |
|---|---|
PSA | Prostate cancer evaluation and monitoring |
CA-125 | Ovarian cancer monitoring |
CEA | Colorectal and several other cancers |
AFP | Liver cancer and certain germ cell tumours |
CA 19-9 | Pancreatic cancer monitoring |
CA 15-3 | Breast cancer monitoring |
CA 27.29 | Breast cancer follow-up |
Beta-hCG | Germ cell tumours and selected cancers |
Tumour marker tests are generally interpreted alongside other diagnostic investigations.
AFP is normally produced during fetal development. In adults, elevated AFP levels may be associated with:
However, AFP levels can also rise in people with chronic liver disease, hepatitis, or cirrhosis. A cancer marker assessment test measuring AFP is therefore only one component of a comprehensive clinical assessment.
CA 19-9 is most commonly associated with pancreatic cancer. Healthcare providers may use it to:
It may also be elevated in non-cancerous conditions such as:
For this reason, CA 19-9 is generally not used as a screening test for people without symptoms [5].
CA 15-3 is primarily associated with breast cancer. Its main clinical uses include:
It is not routinely recommended for breast cancer screening because early-stage cancers may not produce elevated levels.
Like CA 15-3, CA 27.29 is another marker that may be used during breast cancer follow-up. Healthcare providers may request this cancer marker test to help monitor:
Results are interpreted alongside imaging studies and clinical examination rather than in isolation.
Although beta-hCG is widely recognised as a pregnancy hormone, it can also serve as a tumour marker. Healthcare providers may measure beta-hCG when evaluating:
Serial measurements may help monitor treatment effectiveness and detect recurrence in appropriate patients.
Many people assume tumour markers are primarily used to diagnose cancer. In reality, healthcare providers often request a test for cancer markers for several different reasons, including:
The exact role depends on the specific tumour marker and the type of cancer being evaluated.
Tumour marker tests have important limitations. An elevated result does not automatically mean cancer is present. Similarly, a normal result does not completely rule out cancer. Several factors influence tumour marker levels, including:
Because of these limitations, healthcare providers rarely rely on a cancer marker test alone when making clinical decisions. Instead, results are combined with [6]:
This comprehensive approach provides a more accurate assessment.
Usually not. Most tumour marker tests are used together with imaging and biopsy rather than as standalone diagnostic tests.
Several benign medical conditions can increase tumour marker levels, including infections, inflammation, liver disease, and hormonal changes.
Only a limited number have specific screening roles in carefully selected populations. Most are not recommended as routine screening tests for healthy individuals.
The frequency depends on the type of cancer, treatment plan, and your healthcare provider's recommendations.
Not necessarily. Healthcare providers usually interpret trends over time rather than relying on a single value, especially during ongoing monitoring.
Tumour marker testing plays an important role in modern cancer care, particularly when monitoring treatment response, detecting recurrence, and supporting clinical decision-making. However, these tests are only one piece of a much larger diagnostic process.
A cancer marker examination should always be interpreted in the context of your symptoms, medical history, physical examination, imaging studies, and, when appropriate, biopsy results. Elevated levels do not automatically indicate cancer, and normal results do not completely exclude it.
If your healthcare provider recommends a cancer marker test procedure, don't hesitate to ask what the specific marker measures, why it has been ordered, and how the results will be interpreted. Understanding the purpose and limitations of these tests can help you make informed decisions and better understand your overall care plan.
