Prospective Trial of EUS-FNA Versus EUS-FNB Using a Novel Core Biopsy Needle (MUCIN)

Endoscopic ultrasound (EUS) is paramount in the diagnosis and evaluation of cancers involving the gastrointestinal tract. EUS allows for the acquisition of cellular (fine needle aspirate - FNA) or tissue biopsy (fine needle biopsy - FNB) for diagnostic purposes. This has traditionally been done with fine needle aspirate where a needle is inserted into the tumor and potentially malignant cells are extracted for microscopic analysis. More recently, a needle that allows a tissue biopsy for histologic analysis has been FDA approved. The Echotip Procore (Cook Medical) core biopsy needle (ETP), has been demonstrated to provide excellent efficacy for core biopsy samples. Final diagnostic yield using this needle ranges from 80-90% and appears to be significantly greater than EUS-FNA for lesions requiring histology for diagnosis. However, there is currently only limited data from prospective studies comparing EUS-FNA to EUS-FNB with the ETP needle. The investigators propose a randomized, prospective, cross-over study comparing diagnostic accuracy of EUS-FNA to EUS-FNB.

Endoscopic ultrasound (EUS) is paramount in the diagnosis and evaluation of cancers involving the gastrointestinal tract. EUS allows for the acquisition of cellular (fine needle aspirate - FNA) or tissue biopsy (fine needle biopsy - FNB) for diagnostic purposes. This has traditionally been done with fine needle aspirate where a needle is inserted into the tumor and potentially malignant cells are extracted for microscopic analysis. More recently, a needle that allows a tissue biopsy for histologic analysis has been FDA approved. We will compare tissue samples obtained by standard FNA to FNB with a sample size of 140 patients with the primary outcome being diagnostic yield. Each patient will be randomized to FNA or FNA. If after 3 passes the on-site evaluation remains inadequate, the endoscopist will crossover to the other arm.

The investigators' primary outcome measure will assess the diagnostic yield (percentage of patients with a diagnosis) of EUS-FNB (fine-needle biopsy) to provide a final diagnosis of the lesion being sampled. This will be expressed as a percentage.

The investigators' secondary outcome will assess the ability to obtain an adequate specimen for in room cytologic evaluation as determined by our cytopathologist. This will be defined as a sample that is representative (not necessarily diagnostic) of the lesion in question. This will be expressed as a percentage and compared between FNA and FNB

Inclusion Criteria: - 3.1.1 All patients referred for EUS tissue sampling who provide informed consent Exclusion Criteria: 3.2.1 Coagulopathy which is not corrected 3.2.2 Diagnostic EUS determines lesion is not amenable to FNA or FNB