From the Guidelines
CA 19-9 elevation should prompt further diagnostic evaluation, typically starting with imaging studies such as CT scan or MRI of the abdomen, as it can be associated with pancreatic cancer, although it is not specific to cancer and can be elevated in benign conditions 1. When CA 19-9 is found to be elevated, the clinical context is crucial - symptoms, risk factors, and other laboratory findings should guide management.
- The normal range for CA 19-9 is generally below 37 U/mL, with higher levels potentially indicating malignancy.
- Approximately 5-10% of the population cannot produce CA 19-9 due to genetic factors, making it an imperfect screening tool.
- Serial measurements may be useful for monitoring treatment response in patients with confirmed pancreatic cancer.
- If cancer is suspected, prompt referral to gastroenterology or oncology is warranted for comprehensive evaluation, which may include endoscopic ultrasound with possible biopsy. The degree of elevation may correlate with disease burden in malignancy, but even modest elevations should not be dismissed without appropriate investigation, as stated in the most recent guidelines 1.
- CA 19-9 is not recommended for surveillance purposes, but it can be used as an additional diagnostic tool when cancer is suspected.
- Imaging studies such as CT scan or MRI of the abdomen are essential for determining the tumor size, precise burden, and arterial and venous local involvement, which are crucial for staging and treatment decisions 1. In summary, CA 19-9 elevation requires a comprehensive diagnostic approach, considering the clinical context, imaging studies, and potential biopsy, to determine the underlying cause and guide management decisions 1.
From the Research
CA 19-9 Elevation
- CA 19-9 is a serum tumor marker commonly used for pancreatic cancer diagnosis and monitoring therapy in patients with pancreatic adenocarcinoma 2.
- It is normally synthesized by normal human pancreatic and biliary ductal cells, and can be overexpressed in several benign gastrointestinal disorders, leading to false positive elevation 2.
- 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.
- A CA 19-9 serum level of <100 U/mL implies likely resectable disease, whereas levels >100 U/mL suggest unresectability or metastatic disease 3.
- CA 19-9 levels can provide important information regarding prognosis, overall survival, and response to chemotherapy, as well as predict post-operative recurrence 3, 4.
Clinical Applications
- CA 19-9 has achieved a defined role in the diagnosis, prognosis, and monitoring of patients with pancreatic cancer 4.
- A reference value above 200 u/mL in a non-jaundiced patient with a confirming CT scan has a very high predictive value for diagnosis 4.
- CA 19-9 levels have been used successfully in monitoring the response to neoadjuvant therapy 4.
- CA 19-9 can also be used to evaluate the biology of pancreatic cancer and has potential as a therapeutic target 5.
Non-Pancreatic Causes of Elevation
- CA 19-9 levels can be elevated in patients with acute pancreatitis due to gallstone and metabolic/toxic reasons 6.
- Patients with acute pancreatitis due to gallstone were found to have higher CA 19-9 levels compared to patients with metabolic/toxic acute pancreatitis 6.
- Early stage CA 19-9 levels may contribute to standard laboratory tests in determining the etiology of the disease in patients diagnosed with acute pancreatitis 6.