Negative predictive value of endoscopic ultrasound in a large series of patients with a clinical suspicion of pancreatic cancer

Abstract

Objectives: Endoscopic ultrasound (EUS) has been shown to be very accurate in the diagnosis and staging of pancreatic cancer. The accuracy of EUS in predicting the absence of pancreatic cancer in a large series of patients with a clinical suspicion of pancreatic cancer is not well documented. Our aim was to determine the negative predictive value (NPV) of EUS in patients with a suspicion of pancreatic cancer.

Methods: We retrospectively reviewed, from our EUS database (between January 1999 and March 2003), 693 patients who were suspected of having pancreatic cancer and had EUS examinations. A total of 155 patients were found by EUS to have a completely normal pancreas. Indications for EUS in these patients included: weight loss/abdominal pain; and/or pancreatic enlargement/fullness on computed tomography (CT); and/or bile duct/pancreatic duct narrowing on endoscopic retrograde cholangiopancreatography; and/or an elevated CA 19-9. Follow-up information was obtained in 135/155 (87%) patients from patient phone calls and/or physician visits and/or CT scan. The mean follow-up period was 25 months (range 8-48 months).

Results: No patients developed pancreatic cancer during the follow-up period. Following the EUS examination, no work-up was required in 119/135 (88%) of patients. CT scan was performed in 16 patients at 6 months post-procedure, none of which showed a pancreatic mass. The NPV of EUS in excluding pancreatic cancer in those patients with follow-up was 100%.

Conclusion: EUS is highly specific in the diagnosis of pancreatic cancer with a NPV of 100% and obviates the need for further diagnostic testing. In patients with a clinical suspicion of pancreatic cancer, EUS should be considered as the initial diagnostic modality.