EUS-FNB for Solid Pancreatic Lesions: Side-fenestrated Vs Fork-tip Needle
Condition: Biopsy, Fine-needle; Pancreatic Neoplasm
MeSH terms: Pancreatic Neoplasms
Study type: Interventional

Summary: 
      Rationale: Until now there are no prospective studies comparing the 22 gauge and 25 gauge
      side-fenestrated and fork-tip needles.

      In the present study we will compare the two types of needles in terms of histological yield
      for the evaluation of solid pancreatic lesions in the absence of rapid on-site evaluation
      (ROSE). Moreover diagnostic accuracy and the number of passes necessary to achieve the
      maximum diagnostic and histological yield, and safety will be investigated.

      Objectives: To evaluate and compare the histologic retrieval rate of two different EUS-FNB
      needles of the same caliber (22 or 25 gauge). The passes will be 3 for each patient.

      Study design: Randomized monocentric trial. Study population: Patients ≥18 years old,
      referred for EUS-guided tissue sampling of a solid pancreatic mass.

      Intervention: EUS-guided tissue acquisition by mean EUS-FNB, using one of the following FNB
      needles: side-fenestrated 22 gauge, side-fenestrated 25 gauge, fork-tip 22 gauge or fork-tip
      25 gauge.

      Main study parameters/endpoints: The main endpoint is the histologic yield (defined as the
      percentage of a tissue core of at least 550 micron at the greatest axis), obtained at each of
      the 3 needle passes. Secondary endpoints include: i) safety; ii) concordance between
      macroscopic on-site evaluation (MOSE) and histopathological evaluation ; iii) Accuracy using
      1, 2 or 3 passes.
    

Detailed description: 
      Endoscopic ultrasound (EUS) has become an essential procedure in the last decade for
      evaluation of focal pancreatic lesions and for tissue acquisition for diagnostic purposes. In
      these patients the endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) and, more
      recently, the introduction of EUS fine needle biopsy (EUS-FNB), is a safe instrument, with
      high sensitivity (75-98 %) and specificity (71-100%).

      The obtaining of bioptic tissue samples reduces the need for rapid on site-evaluation (ROSE)
      and allows an easier interpretation of the diagnosis even by non-expert pathologist. It also
      makes possible to perform ancillary investigations such as immunohistochemical, often useful
      for the differential diagnosis.

      Two different EUS-FNB needles are available: the side-fenestrated reverse bevel and the
      fork-tip forward-acquiring". Both are available in 25, 22 and 19 gauge. The 22 gauge is the
      most commonly used since it combines the ease of use of small-sized caliber with the
      advantages of larger sized needles. The 25 gauge is universally recognized as the most
      manageable and flexible needle and is preferred when the lesion is small (<20mm) or is in
      "difficult" conditions (lesion localized to the uncinate process or to distal tail, lesion
      distant from the transducer > 15mm, need to cross > 1cm of healthy pancreas, angled position
      of the instrument).

      There are no prospective studies comparing the 22 and 25 gauge side-fenestrated and fork-tip
      needles. We therefore propose a prospective randomized study, to compare the two types of
      needles in terms of histologic and diagnostic yield, number of passes necessary to reach it
      in solid pancreatic lesions, in the absence of ROSE.

      This is a randomized single center trial with two parallel arms in a (1:1) ratio. Consecutive
      patients with solid pancreatic masses and an indication to perform EUS-guided tissue
      acquisition will be evaluated and, if eligible, will be enrolled into the study.
      Randomization will take place after the lesion will have been visualized with EUS and the
      patient will be found suitable for inclusion.

      The choice of needle gauge (22 or 25 gauge) will be at the discretion of the endosonographer
      in relation to the difficulty/risk of the procedure; therefore, two randomization lists will
      be drawn up, (one for the 22 gauge and one for the 25 gauge).

      The choice of the needle gauge will be done before randomization so that the choice of the
      needle does not create bias in the results. The pathologist will be blinded to the needle
      caliber and type.

      The sample size has been calculated for the primary outcome (histologic retrieval rate) using
      a group sequential design to define a proper interim analysis after at least 50% enrolment.
      The histologic yield of the two needle types can be summarized as follows:

      22 gauge: 77% and 92% for the side-fenestrated and the fork-tip, respectively. 25 gauge:
      60.5% and 85% for the side-fenestrated and the fork-tip, respectively.

      With a type I error α of 5% and a power 1 - β of 80%, the total required sample size amounts
      to 330 patients (210 patients for 22G group and 120 patients for 25G group). Considering that
      18% of patients must be added to counteract the estimated and lost drop-out rate at
      follow-up, overall 362 patients will be needed (196 patients for the 22G group and 112
      patients for the 25G group).

      Based on sample size calculation the two lists will consist in 24 blocks of 8 patients and 1
      block of 4 patients for the 22G group and 14 blocks of 8 patients for the 25G group.
    

Intervention name(s): Histologic evaluation
Intervention type(s): Diagnostic Test
Intervention description(s): Samples collected by EUS-FNB without ROSE will be processed as histologic samples
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: pancreatic cancer, endoscopic ultrasound, fine needle biopsy