Using an endoscopic distal cap to collect pancreatic fluid from the ampulla (with video)

Abstract

Duodenal collections of pancreatic fluid can be used as a source of mutations and other markers of pancreatic ductal neoplasia, but admixing pancreatic juice with duodenal contents lowers the concentrations of mutations. Collecting pancreatic fluid directly from the ampulla could yield a purer sample of pancreatic fluid. We used an endoscopic distal cap attachment to "cap" the ampulla and collect secretin-stimulated pancreatic fluid samples for 5 minutes from 81 patients undergoing pancreatic evaluation as part of the Cancer of the Pancreas Screening studies. We compared mutation concentrations (K-ras and GNAS) measured by droplet-digital PCR (ddPCR) in "cap-collected juice" samples to those found in juice samples obtained from 77 patients collected by aspiration from the duodenal lumen without capping the ampulla. Among all subjects, mutation concentrations were higher in pancreatic juice samples collected using the endoscopic cap method (median, .028%; IQR, 0-.077) compared with the noncap-collected (median, .019%; IQR, 0-.044; P= .055). Among pancreatic juice samples with detectable mutations, mutation concentrations were higher in the cap-collected juice samples than in those collected without the cap (.055%; IQR, .026-.092 vs .032%; IQR, .020-.066; P= .031). Collecting pancreatic juice directly from the ampulla using an endoscopic distal cap yields higher concentrations of pancreatic fluid mutations.