Feasibility and yield of a novel 22-gauge histology EUS needle in patients with pancreatic masses: a multicenter prospective cohort study

The option of obtaining tissue samples for histological examination during endoscopic ultrasound (EUS) has theoretical and practical advantages over cytology alone. The aim of this study was to evaluate the feasibility, yield, and diagnostic accuracy of a new EUS 22-G fine-needle biopsy (FNB) device in patients with solid pancreatic masses in a multicenter, prospective study. All consecutive patients who underwent EUS-guided fine-needle biopsy (EUS-FNB) using a newly developed 22-G FNB needle between September 2010 and October 2010 were enrolled in the study. The EUS-FNB technique was standardized among the participating endoscopists. Only a single needle pass was performed. A total of 61 patients (35 males, mean age 64.2 +/- A 12.4 years) with solid pancreatic masses with a mean size of 32.4 +/- A 8.5 mm (range 13-90 mm) participated. EUS-FNB was performed through the duodenum in 35 cases (57.4 %) and was technically feasible in all but one of the 61 (98.4 %) patients without complications. Tissue samples for histological examination were obtained from 55 patients (90.2 %) and were deemed adequate in 54 of the cases (88.5 %). The diagnoses established by EUS-FNB were adenocarcinoma (39 patients), neuroendocrine tumors (5), chronic focal pancreatitis (5), sarcoma (2), lymphoma (1), acinar cellular tumor (1), and pancreatic metastasis from renal cell carcinoma (1). In an intention-to-treat (ITT) analysis, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for the histologic diagnosis of a pancreatic mass were 87.5, 100, 100, 41.7, and 88.5 %, respectively. EUS-FNB was technically feasible in 98 % of patients with a solid pancreatic mass. A suitable sample for histological evaluation was obtained in 88.5 % of the cases after only one single needle pass. The apparently low negative predictive value is likely to be improved by increasing the number of needle passes.