Impact of prior biliary stenting on diagnostic performance of endoscopic ultrasound for mesenteric vascular staging in patients with head of pancreas and periampullary malignancy

Objective The diagnostic performance of endoscopic ultrasound (EUS) for stratification of head of pancreas and periampullary tumours into resectable, borderline resectable and locally advanced tumours is unclear as is the effect of endobiliary stents. The primary aim of the study was to assess the diagnostic performance of EUS for resectability according to stent status. Design A retrospective study was performed. All patients presenting with a solid head of pancreas mass who underwent EUS and surgery with curative intent during an 8-year period were included. Factors with possible impact on diagnostic performance of EUS were analysed using logistic regression. Results Ninety patients met inclusion criteria and formed the study group. A total of 49 (54%) patients had an indwelling biliary stent at the time of EUS, of which 36 were plastic and 13 were self-expanding metal stents (SEMS). Twenty patients underwent venous resection and reconstruction (VRR). Staging was successfully performed in 100% unstented cases, 97% plastic stent and 54% SEMS, p<0.0001. In successfully staged patients, sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) for classification of resectability were 70%, 70%, 70%, 42% and 88%. For vascular involvement (VI), sensitivity, specificity, accuracy, PPV and NPV were 80%, 68%, 69%, 26% and 96%. Increasing tumour size OR 0.53 (95% CI, 0.30 to 0.95) was associated with a decrease in accuracy of VI classification. Conclusions EUS has modest diagnostic performance for stratification of staging. Staging was less likely to be completed when a SEMS was in situ. Staging EUS should ideally be performed before endoscopic retrograde cholangiopancreatography and biliary drainage.