ERCP or EUS for tissue diagnosis of biliary strictures? A prospective comparative study

The accuracy of ERCP-based brush cytology or forceps biopsy for tissue diagnosis is relatively low (usually not exceeding 70%). By contrast, reported accuracy rates for EUS-guided FNA of pancreatobiliary masses are over 80%. This prospective study compared these two modalities for the first time in the diagnosis of indeterminate biliary strictures and pancreatic tumors.

Fifty consecutive patients (29 men, 21 women; mean age 62.1 years) with obstructive jaundice in whom a tissue diagnosis was required were included. During ERCP, intraductal specimens were obtained with a forceps and with two different types of brush (conventional and spiral suction) in random order. During EUS, only visible mass lesions or localized bile duct wall thickening were aspirated (22-gauge needle), with at least two passes yielding material sufficient for assessment. A cytopathologist was not present in the procedure room to evaluate specimen adequacy. The reference methods were surgery, other biopsy results, follow-up until death, or the conclusion of the study (mean follow-up 20 months).

The final diagnoses were malignancy, 28 (16 pancreatic, 12 biliary), and benign biliary stricture, 22. Sensitivity and specificity for ERCP-guided biopsy were 36% and 100%, respectively; for ERCP-guided cytology (when using conventional and spiral suction brushes), 46% and 100%, respectively; and for EUS-guided FNA, 43% and 100%, respectively. If the punctured lesions are considered (n=28) alone, the sensitivity of EUS-guided FNA was 75%. In general, sensitivity was better for ERCP-based techniques in the subgroup biliary tumor (ERCP 75% vs. EUS 25%), whereas EUS-guided biopsy was superior for pancreatic mass (EUS 60% vs. ERCP 38%).

For biliary strictures, combined ERCP- and EUS-guided tissue acquisition seems to be the best approach to tissue diagnosis. From a clinical standpoint, it appears reasonable, when a tissue diagnosis is required, to start with ERCP if biliary malignancy is suspected and with EUS when a pancreatic tumor is thought to be the cause of a biliary stricture.