What does an elevated Carbohydrate Antigen 19-9 (CA-19-9) level indicate?

From the Guidelines

Elevated CA-19-9 levels may indicate pancreatic cancer, but can also be associated with other conditions, and a single elevated reading requires clinical context and further investigation. CA-19-9 is a tumor marker primarily used to monitor pancreatic cancer treatment response rather than for initial diagnosis. Normal levels are typically below 37 U/mL, with higher values potentially suggesting pancreatic, biliary, colorectal, or gastric cancers. However, elevated levels can also occur in non-cancerous conditions like pancreatitis, liver disease, gallstones, or cholangitis. About 5-10% of the population cannot produce CA-19-9 even with cancer present. The degree of elevation may correlate with tumor burden, but a single elevated reading requires clinical context and further investigation.

Key Points

• CA 19-9 is the most useful tumour marker in pancreatic cancer 1
• Staging of the patient is initially done by CT scan
• EUS provides some complementary information and allows biopsy of the tumour 1
• MRI should be discussed, especially in cystic lesions 1 If you have an elevated CA-19-9, your doctor will likely recommend additional tests such as imaging studies (CT, MRI, or endoscopic ultrasound) and possibly tissue sampling to determine the cause. The marker is most valuable when tracked over time to assess treatment effectiveness in patients with confirmed cancer.

Diagnosis and Staging

Diagnosis and staging of pancreatic cancer should be done using a combination of imaging modalities, including CT, MRI, and EUS, as well as tumor markers like CA 19-9 1.

Treatment and Follow-up

Treatment and follow-up of pancreatic cancer should be individualized based on the patient's specific condition, and CA 19-9 levels can be used to monitor treatment response and detect potential recurrence 1. In terms of morbidity, mortality, and quality of life, it is essential to approach elevated CA-19-9 levels with caution and consider the potential for false positives or false negatives, as well as the need for further testing and evaluation to determine the underlying cause.

Morbidity, Mortality, and Quality of Life

Elevated CA-19-9 levels can have significant implications for morbidity, mortality, and quality of life, particularly if they are indicative of pancreatic cancer or other serious conditions. Therefore, it is crucial to prioritize further testing and evaluation to determine the underlying cause of elevated CA-19-9 levels and to develop an appropriate treatment plan.

Further Testing and Evaluation

Further testing and evaluation, including imaging studies and tissue sampling, are necessary to determine the underlying cause of elevated CA-19-9 levels and to develop an appropriate treatment plan. In conclusion, elevated CA-19-9 levels require careful consideration and further evaluation to determine the underlying cause and to develop an appropriate treatment plan, with a focus on minimizing morbidity, mortality, and improving quality of life.

From the Research

Elevation of CA-19-9 Level

Elevation of CA-19-9 level can be an indicator of various conditions, including:

• Pancreatic cancer: Studies have shown that CA-19-9 serum levels are higher in patients with pancreatic cancer than in those without malignancy or with neuroendocrine tumors 2, 3.
• Cholangiocarcinoma: CA-19-9 serum levels were found to be elevated in patients with cholangiocarcinoma, with a sensitivity of 59.3% and specificity of 82% 2.
• Ampullary and periampullary carcinomas: Elevated CA-19-9 levels were also found in patients with ampullary and periampullary carcinomas, although the sensitivity and specificity were lower compared to pancreatic cancer 2.
• Benign conditions: CA-19-9 levels can also be elevated in benign conditions such as choledocholithiasis, cholangitis, and biliary manipulation 4, 5.

Interpretation of CA-19-9 Levels

When interpreting CA-19-9 levels, it is essential to consider the entire clinical context, including:

• Symptomatic patients: CA-19-9 serum levels have a sensitivity and specificity of 79-81% and 82-90%, respectively, for the diagnosis of pancreatic cancer in symptomatic patients 3.
• Asymptomatic patients: CA-19-9 is not useful as a screening marker for pancreatic cancer in asymptomatic patients due to its low positive predictive value 3.
• Obstructive jaundice: CA-19-9 elevation in non-malignant jaundice can result in a fall in specificity, and elevated values should be repeated after relief of jaundice 6.

Clinical Utility of CA-19-9

CA-19-9 is the most extensively validated pancreatic cancer biomarker, with multiple clinical applications, including:

• Diagnosis: CA-19-9 can aid in the diagnosis of pancreatic cancer, particularly in symptomatic patients 2, 3.
• Prognosis: Pre-operative CA-19-9 serum levels can provide useful prognostic information, with patients having normal levels (<37 U/mL) having a prolonged median survival compared to those with elevated levels (>37 U/mL) 3.
• Treatment monitoring: CA-19-9 serum levels can be used to monitor response to chemotherapy and predict post-operative recurrence 3.