Preoperative next-generation sequencing of pancreatic cyst fluid is highly accurate in cyst classification and detection of advanced neoplasia.

Abstract

DNA-based testing of pancreatic cyst fluid (PCF) is a useful adjunct to the evaluation of pancreatic cysts (PCs). Mutations in <i>KRAS</i>/<i>GNAS</i> are highly specific for intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs), while <i>TP53</i>/<i>PIK3CA</i>/<i>PTEN</i> alterations are associated with advanced neoplasia. A prospective study was performed to evaluate preoperative PCF DNA testing. Over 43-months, 626 PCF specimens from 595 patients were obtained by endoscopic ultrasound (EUS)-fine needle aspiration and assessed by targeted next-generation sequencing (NGS). Molecular results were correlated with EUS findings, ancillary studies and follow-up. A separate cohort of 159 PCF specimens was also evaluated for <i>KRAS</i>/<i>GNAS</i> mutations by Sanger sequencing. <i>KRAS/GNAS</i> mutations were identified in 308 (49%) PCs, while alterations in <i>TP53/PIK3CA/PTEN</i> were present in 35 (6%) cases. Based on 102 (17%) patients with surgical follow-up, <i>KRAS/GNAS</i> mutations were detected in 56 (100%) IPMNs and 3 (30%) MCNs, and associated with 89% sensitivity and 100% specificity for a mucinous PC. In comparison, <i>KRAS/GNAS</i> mutations by Sanger sequencing had a 65% sensitivity and 100% specificity. By NGS, the combination of <i>KRAS/GNAS</i> mutations and alterations in <i>TP53/PIK3CA/PTEN</i> had an 89% sensitivity and 100% specificity for advanced neoplasia. Ductal dilatation, a mural nodule and malignant cytopathology had lower sensitivities (42%, 32% and 32%, respectively) and specificities (74%, 94% and 98%, respectively). In contrast to Sanger sequencing, preoperative NGS of PCF for <i>KRAS</i>/<i>GNAS</i> mutations is highly sensitive for IPMNs and specific for mucinous PCs. In addition, the combination of <i>TP53</i>/<i>PIK3CA</i>/<i>PTEN</i> alterations is a useful preoperative marker for advanced neoplasia.