The Accuracy of Endoscopic Ultrasound (EUS)-Guided Fine Needle Aspiration (FNA) for Diagnosing Solid Pancreatic Lesions Using a New 25-Gauge Needle System

Abstract

Introduction: EUS-FNA has enhanced our ability to diagnose pancreatic masses. Most of the published data is based on the use of a 22-gauge needle. The aim of this study was to evaluate our center's experience with a new disposable 25-gauge needle system in the diagnosis of solid pancreatic lesions. Methods: Our institution began utilizing this FDA approved 25-gauge EUS-FNA needle system (Echotip, Wilson Cook, Winston Salem, NC) in 2/2001. All patients referred for EUS evaluation of solid pancreatic mass between 2/2001 and 12/2002 were reviewed. Patient demographics, clinical history including follow-up, and pathology findings were recorded. Cytopathology was compared with operative histopathology in patients who had surgery. Patients who did not have surgery were followed clinically. Results: A total of 163 patients (mean age 66, 88 M/75 F) underwent EUS-FNA for solid pancreatic lesions using the 25-gauge needle. FNA was consistent with pancreatic malignancy in 48% (78/163) while 45% (74/163) had no evidence of malignancy. In the remaining 7% (11/163), biopsy was inconclusive. No complications were reported. Of the pancreatic cancer patients, 96% (75/78) had adenocarcinoma and 4% (3/78) had other malignancies. In the group with a definitive FNA diagnosis, 14% (23/163) underwent surgery and operative histopathology was compared with FNA cytopathology. There was one false-negative and no false-positive diagosis; and the sensitivity, specificity, PPV, and NPV were 94%, 100%, 100%, and 86% respectively. In the false-negative case, patient had cytologic evidence of chronic pancreatitis. In patients with an inconclusive FNA, 27% (3/11) had surgery and 2 had adenocarcinoma. The remaining 84% (137/163) of patients who did not undergo surgery were followed clinically. The mean survival for patients with a positive, negative, and inconclusive FNA was 11, 23, and 14 months respectively. Conclusions: 1. EUS-FNA using a 25-gauge needle system can accurately and safely provide a cytologic diagnosis of pancreatic masses. 2. The patient who had a false-negative FNA diagnosis had chronic pancreatitis, confirming previous reports that cytologic evaluation of pancreatic tissue in the setting of chronic inflammation can be difficult. 3. Studies with larger sample size and randomized arms are now needed to further assess the accuracy and complication rate of this smaller needle system.