Infuence of Biliary Stenting (BS) on Endoscopic Ultrasonography (EUS) Detection and Staging Accuracy of Pancreaticobiliary Neoplasms (PN)

Abstract

Background: EUS has been shown to be an highly accurate test for PN imaging which has a fundamental influence on patients management. However, the timing when to perform EUS in the diagnostic algorithm of PN is less defined. In clinical practice EUS is often requested in patients whose diagnosis and staging are still uncertain after endoscopic retrograde cholangiopancreatography (ERCP) with stent positioning in the bile duct. Aim of this study was to assess the influence of biliary stenting on EUS detection and staging accuracy rates in pts with PN. Material and Methods: Our records were reviewed for patients who underwent EUS for staging of PN and had a prior stent positioning in the bile duct. Time period: July 2002-July 2004. EUS examinations were performed either with a radial mechanical scanning or with a sector electronic scanning Olympus echoendoscope. The influence of a biliary stent at the time of EUS on the diagnosis and staging was evaluated. EUS results could be controlled by comparison with surgical pathological staging when available or, alternatively, by follow up data including EUS-fine needle aspiration results. Results: Twenty-one patients were identified (13M/8F; mean age 61.2 yrs, 34-80 yrs) who had a transpapillary biliary stent at the time of EUS (19 plastic and 2 metallic stents). Reason for stent positioning at the time of ERCP was obstructive jaundice suspicious for malignancy. Biliary stenting compromised to some extent all EUS examinations because of intervening air in the duodenum and material artifacts in the bile duct. EUS results were as follows: compatible with PN in 14/21; negative for PN in 4/21; ampullary neoplasm in 2/21; and chronic pancreatitis in 1/21. In 13/14 cases with EUS compatible with PN who underwent subsequent surgical operation, EUS vs. surgical pathology T staging results were: T1 = 0 vs. 1 pt; T2 = 1 vs. 1 pts; T3 = 7 vs. 2 pts; T4 = 5 vs. 9 pts. T staging was underestimated by EUS in 4/13 pts. and overestimated in only 1/13 pt. (EUS T3 vs surgical T1). Three/4 pts. with EUS negative for PN were subsequently found to have PN (2 adenocarcinoma and 1 cholangiocarcinoma). Overall EUS detection rate for PN was 84%. Conclusion: Our data confirm that impact of EUS on PN diagnosis is substantial. Biliary stent insertion adversely influenced EUS detection rate and T stage accuracy of PN. Understaging was more likely to occur than overstaging. Every effort should be taken to perform EUS prior to biliary stent insertion.