Endoscopic Ultrasound Versus Endoscopic Retrograde Cholangiopancreatography (ERCP) Tissue Sampling for the Diagnosis of Suspected Pancreatico-Biliary Cancer

The two most commonly used methods to biopsy suspected pancreaticobiliary masses are (1) endoscopic ultrasound guided fine-needle aspiration (EUS-FNA) and (2) cytology brush biopsies obtained during endoscopic retrograde cholangiopancreatography (ERCP). At most centers, the specific method used depends on the availability of the technology and local expertise. Although it is believed that EUS-FNA is more accurate than ERCP brushings, there have been no head-to-head comparisons. The investigators' hypothesis is that EUS-FNA is superior to ERCP in obtaining tissue biopsies of pancreaticobiliary tumors, and the investigators aim to directly compare the two techniques.