CA19-9 Tumour Marker for Pancreatic Cancer: A Comprehensive Guide

Pancreatic cancer occurs in the pancreas, an organ located behind the stomach. This type of cancer involves the rapid and uncontrolled growth of abnormal cells within the pancreas that have the potential to spread throughout the body.

To detect pancreatic cancer, medical specialists use a combination of imaging tests, such as CT scans and MRIs, and laboratory tests, including blood tests. These blood tests often include the measurement of tumour markers, such as CA19-9.

The CA19-9 tumour marker plays an important role in the detection and management of pancreatic cancer. It provides valuable information about the presence and progression of the disease. In this blog, you will learn everything you need to know about CA19-9.

What is CA19-9?

Antigens are substances that cause the immune system to respond. Carbohydrate antigen (CA) 19-9 is a type of antigen released by pancreatic cancer cells. It can also be referred to as a tumour marker.

The CA19-9 levels are used together with imaging studies like CT scans and MRIs. While these imaging tests provide a visual look at the presence of a tumour, CA19-9 adds a biochemical layer to the diagnostic process, enhancing the overall evaluation and helping to confirm suspicions about the disease.

When imaging results are not definitive, CA19-9 levels can be important in deciding whether to proceed with a biopsy. Elevated levels might encourage doctors to opt for a biopsy sooner rather than later, which could lead to an earlier diagnosis and potentially more effective treatment options.

How CA19-9 Levels Are Measured?

CA19-9 levels are measured using a blood test, specifically an enzyme-linked immunosorbent assay (ELISA) or a radioimmunoassay.

1. Blood Sample Collection

A sample of the patient’s blood is collected, typically from a vein in the arm.

2. Laboratory Analysis

The blood sample is then analysed in the laboratory. The CA19-9 present in the sample binds to specific antibodies coated on a plate or mixed with a radioactive substance, depending on the assay used.

3. Quantifying CA19-9 Levels

The amount of CA19-9 is quantified by measuring the colour change in the ELISA test or the radioactivity in the radioimmunoassay. The results are typically given in units per millilitre (U/mL).

The test’s accuracy can be affected by various factors, including other health conditions the patient may have, such as liver and gallbladder diseases, which can also elevate CA19-9 levels.

Interpretation of CA19-9 Test Results

The reference range for CA19-9 is typically under 37 U/mL, but interpreting these levels requires careful consideration of the clinical context. The value of the test result may vary based on other symptoms, additional test outcomes, and the patient’s health history.

Normal Levels

A CA19-9 level within the normal range may suggest the absence of pancreatic cancer, but it is not conclusive, especially if clinical symptoms or imaging studies indicate otherwise.

Elevated Levels

Elevated CA19-9 levels can suggest the presence of pancreatic cancer, particularly in symptomatic people. However, levels can also be elevated in other conditions, such as cirrhosis, cholestasis, and inflammatory bowel disease.

Very High Levels

Significantly high levels of CA19-9, often over 1000 U/mL, are more strongly associated with pancreatic cancer, although this is not definitive.

It is also important to note that approximately 10% of the population cannot produce CA19-9 due to their genetic makeup, which can result in false negative results in these people.

Factors That May Affect CA19-9 Levels

Several factors can affect CA19-9 levels, making it important to consider these factors when interpreting the results. For example, certain medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), can cause a temporary increase in CA19-9 levels. Additionally, conditions like pancreatitis and biliary obstruction can also lead to elevated CA19-9 levels. Therefore, it is important for medical specialists to take these factors into account when assessing CA19-9 results.

Limitations of CA19-9 as a Diagnostic Tool

While CA19-9 is useful in detecting pancreatic cancer, its role as a standalone diagnostic tool is limited due to several factors:

  • Lack of Specificity: CA19-9 is not exclusive to pancreatic cancer. Elevated levels can also occur in other cancers and benign conditions like liver and gallbladder diseases, and even in healthy individuals.
  • False Negatives: Some people genetically cannot produce CA19-9, which can lead to false negatives, meaning a normal CA19-9 level does not necessarily rule out pancreatic cancer.
  • Not Suitable for Screening: The marker’s lack of specificity and the potential for false negatives make CA19-9 unsuitable for general population screening for pancreatic cancer.
  • Influence of Other Factors: Levels of CA19-9 can also be affected by non-cancerous conditions impacting the liver, bile ducts, and other organs, complicating the interpretation of test results.

Despite these limitations, CA19-9 is helpful in a clinical setting to monitor how well a treatment is working. Doctors often use changes in CA19-9 levels to assess the effectiveness of a treatment regimen, helping guide ongoing care decisions.

Conclusion

In conclusion, CA19-9 has emerged as a valuable tool in the diagnosis and management of pancreatic cancer. While it has its limitations, CA19-9 provides valuable information about the presence and progression of the disease. Its measurement, alongside other diagnostic tests, allows for a more accurate diagnosis and better treatment decisions.

If you or someone you know is facing symptoms of pancreatic cancer, don’t hesitate to reach out. Our team is ready to assist you. Contact us today to book an appointment and ensure you get the right diagnosis and treatment.