From the Guidelines
The most commonly used tumor marker for pancreatic cancer is CA 19-9 (carbohydrate antigen 19-9). This glycoprotein is elevated in approximately 70-80% of patients with pancreatic cancer, making it the primary biomarker used for this malignancy 1.
Key Points
- CA 19-9 is particularly useful for monitoring treatment response and detecting recurrence in patients with known pancreatic cancer.
- It has limitations as a screening tool due to its imperfect sensitivity and specificity.
- False positives can occur in benign conditions like pancreatitis, cholangitis, and other gastrointestinal disorders.
- About 5-10% of the population cannot produce CA 19-9 due to Lewis antigen negativity, resulting in false negatives.
- While other markers like CEA (carcinoembryonic antigen) and CA-125 may sometimes be used, CA 19-9 remains the gold standard tumor marker for pancreatic cancer in clinical practice 1.
Clinical Use
CA 19-9 is used to monitor disease progression and response to treatment in patients with pancreatic cancer.
- It is also used to detect recurrence in patients who have undergone treatment for pancreatic cancer.
- However, it is not recommended as a screening tool for the general population due to its low sensitivity and specificity.
Limitations
- CA 19-9 is not specific to pancreatic cancer and can be elevated in other conditions, such as benign biliary obstruction or cholangitis.
- It is not recommended for surveillance purposes in patients with primary sclerosing cholangitis (PSC) or other benign liver diseases 1.
From the Research
Tumor Markers for Pancreatic Cancer
- The most commonly used tumor marker for pancreatic cancer is CA 19-9 2, 3, 4, 5.
- CA 19-9 is a cell surface glycoprotein complex that is overexpressed in pancreatic ductal adenocarcinoma (PDAC) 5.
- The sensitivity and specificity of CA 19-9 for the diagnosis of pancreatic cancer in symptomatic patients are 79-81% and 82-90%, respectively 3, 4.
Clinical Applications of CA 19-9
- CA 19-9 is used for diagnosing, managing, and prognosticating PDAC 5.
- Elevated CA 19-9 levels are used as an indication for surgery in suspected benign pancreatic conditions 5.
- CA 19-9 is also used as an adjunct in diagnosing cholangiocarcinoma 5.
- The potential value of CA 19-9 extends to gastrointestinal cancers, such as colorectal and oesophageal cancer, and beyond the gastrointestinal tract, including urological, gynecological, pulmonary, and thyroid pathologies 5.
Limitations of CA 19-9
- CA 19-9 has poor sensitivity and can give false negative results in Lewis negative phenotype (5-10%) 3, 4.
- CA 19-9 can also give false positive results in the presence of obstructive jaundice (10-60%) 3, 4.
- CA 19-9 is not useful as a screening marker due to its low positive predictive value (0.5-0.9%) 4.
- The CA 19-9 tumor marker should not be used in isolation to trend chemotherapy response in patients with pancreatic ductal adenocarcinoma 6.