From the Guidelines
A CT scan to rule out pancreatic cancer should be ordered when patients present with unexplained jaundice, unexplained weight loss, persistent upper abdominal or mid-back pain, new-onset diabetes in older adults without risk factors, or unexplained digestive problems like nausea, vomiting, or changes in stool. The combination of symptoms is particularly concerning, especially when they develop rapidly over weeks to months. According to the most recent guidelines 1, a contrast-enhanced CT scan is the preferred initial imaging test, ideally using a pancreatic protocol with arterial and venous phase imaging. Patients should fast for 4-6 hours before the scan and should inform their doctor about any allergies to contrast agents, kidney problems, or if they are pregnant. The CT scan works by creating detailed cross-sectional images that can detect masses, ductal dilation, and vascular involvement. Early detection is crucial as pancreatic cancer is often diagnosed at advanced stages, contributing to its poor prognosis. If the CT findings are inconclusive but clinical suspicion remains high, additional imaging such as MRI/MRCP or endoscopic ultrasound may be necessary, as suggested by 1 and 1.
Key Symptoms for CT Scan
- Unexplained jaundice
- Unexplained weight loss
- Persistent upper abdominal or mid-back pain
- New-onset diabetes in older adults without risk factors
- Unexplained digestive problems like nausea, vomiting, or changes in stool
Imaging Protocol
- Contrast-enhanced CT scan
- Pancreatic protocol with arterial and venous phase imaging
- Patients should fast for 4-6 hours before the scan
- Inform doctor about any allergies to contrast agents, kidney problems, or if they are pregnant
Additional Imaging
- MRI/MRCP
- Endoscopic ultrasound
- PET/CT scan may be considered after formal pancreatic CT protocol in “high-risk” patients to detect extra pancreatic metastases, as noted in 1.
It is essential to note that the role of PET/CT scan remains unclear, and it is not a substitute for high-quality, contrast-enhanced CT, as stated in 1. Endoscopic ultrasound (EUS) may be complementary to CT for staging, and EUS-directed FNA biopsy is preferable to a CT-guided FNA in patients with resectable disease, as suggested by 1.
From the Research
Symptoms to Order CT Scan for Pancreatic Cancer
To determine when to order a CT scan to rule out pancreatic cancer, the following symptoms and conditions should be considered:
- Abdominal pain or discomfort, particularly in the upper abdomen 2, 3, 4
- Unexplained weight loss 2, 3, 4
- Jaundice or yellowing of the skin and eyes 2, 3, 4
- Nausea and vomiting 2, 3, 4
- Fatigue or weakness 2, 3, 4
- New-onset diabetes or changes in blood sugar control 2, 3, 4
CA 19-9 Levels and CT Scan
CA 19-9 is a tumor marker that can be elevated in pancreatic cancer. The following CA 19-9 levels may indicate the need for a CT scan:
- A CA 19-9 level above 200 u/mL in a non-jaundiced patient may indicate pancreatic cancer, especially if accompanied by a confirming CT scan 5
- A CA 19-9 level above 37 u/mL may indicate a poorer prognosis and a higher risk of unresectable disease 3, 4
- A CA 19-9 level above 100 u/mL may suggest unresectable disease or metastatic disease 3, 4
Diagnostic Accuracy of CT Scan
The diagnostic accuracy of CT scan for pancreatic cancer is high, with a positive predictive value of 98% and a negative predictive value of 86% 6. However, CT scan should be used in conjunction with other diagnostic tools, such as CA 19-9 assessment and fine-needle aspiration biopsy, to confirm the diagnosis of pancreatic cancer.