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EUS-guided Fine Needle Aspiration (FNA) With and Without the Use of a Stylet

This study has been completed.
Information provided by (Responsible Party):
Washington University School of Medicine Identifier:
First received: March 14, 2011
Last updated: November 24, 2014
Last verified: November 2014
The purpose of this study is to determine that there is no difference in final diagnosis of FNA specimens without a stylet, compared to using a stylet, when examined by a skilled cytopathologist.

Condition Intervention
Biopsy, Fine-Needle
Biopsy, Fine-Needle/Methods
Device: FNA with and without a stylet

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Single Blind (Outcomes Assessor)
Primary Purpose: Diagnostic
Official Title: Randomized Controlled Trial of Endoscopic Ultrasound Guided Fine Needle Aspiration of Solid Lesions With and Without a Stylet

Further study details as provided by Washington University School of Medicine:

Primary Outcome Measures:
  • Compare Adequacy of Diagnoses in Passes With and Without a Stylet [ Time Frame: At the time of EUS-FNA procedure (Day 1) ]

    The number of passes was determined by the lesion site and mirrored clinical practice (6 passes for pancreatic/other lesions and 4 passes for lymph nodes). The order of these passes was determined by a preprinted randomization sequence kept in an opaque sealed envelope that was opened by the research coordinator or EUS technologist after enrollment. Each participant had an equal number of passes with stylet and without stylet.

    There was no communication between the endosonographer and the cytopathologist regarding the adequacy of the specimen or diagnosis until all passes had been completed. The on-site evaluation of smears was performed to assess cellular adequacy and to assess the need for any additional passes. Additional passes were made at the discretion of the endosonographer as clinically indicated but were not included in the final analysis. The cytology slides were evaluated by 3 experienced cytopathologists who were all blinded to the stylet status of the passes.

Secondary Outcome Measures:
  • Degree of Cellularity [ Time Frame: At the time of EUS-FNA procedure (Day 1) ]
    Percentage of area of slide that contains cells of the representative lesion

  • Degree of Cellularity [ Time Frame: At the time of EUS-FNA procedure (Day 1) ]
    Number of cells per slide

  • Adequacy of Specimen [ Time Frame: At the time of EUS-FNA procedure (Day 1) ]
  • Contamination [ Time Frame: At the time of EUS-FNA procedure (Day 1) ]
    Percentage of area of slide that represents GI contamination

  • Amount of Blood [ Time Frame: At the time of EUS-FNA procedure (Day 1) ]

Enrollment: 137
Study Start Date: July 2010
Study Completion Date: July 2011
Primary Completion Date: July 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: With Stylet & Without Stylet
There will only be one arm in this study. This arm will undergo EUS-guided FNA with the use of a stylet for half of their FNA passes and without a stylet for the other half. Patients will be exposed to an equal number of passes with and without a stylet. Each pass will be individually assessed by a skilled cytopathologist who is blinded to the technique used. We will compare the adequacy of both techniques to determine whether or not a stylet leads to a higher diagnostic accuracy rate in patients with solid lesions.
Device: FNA with and without a stylet
If the patient agrees to enrollment in the study, the initial stage of the EUS exam will be performed in the usual manner. If a solid lesion that requires FNA is identified, an envelope will be opened which contains a computer generated randomization sequence for all passes. These sequences will be generated by a web-based program at Passes will be made based on the randomization, either with or without a stylet. Six passes (three with a stylet and three without a stylet) will be performed on solid lesions and four passes (two with and two without a stylet) will be performed on lymph nodes. Additional passes will be made at the discretion of the endosonographer as clinically indicated but will not be included in the data.
Other Name: Cook Medical EchoTip® Ultra Endoscopic Ultrasound Needles

Detailed Description:

Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) is a highly accurate method for cytologic diagnosis of malignancy and is routinely performed to diagnose and stage pancreatobiliary, esophageal, gastric, rectal malignancies and subepithelial gastrointestinal lesions. There are variations in EUS-FNA technique including the use of suction, the area of the lesion to target (center versus periphery), gauge of needle, and use of a stylet.

The stylet is a metal wire which is included in the needle assembly. The use of a stylet is used purely for mechanical purposes, not for the protection or safety of the patients. It is thought that the stylet prevents the needle from becoming clogged with gastrointestinal epithelial cells or mucus. To our knowledge, comparing the diagnostic accuracy of EUS-FNA with a stylet to the accuracy without a stylet has not been studied.

The optimal technique for EUS-FNA has not been established. The reported accuracy rate of EUS-FNA (which contains heterogeneous sampling techniques, including with and without a stylet) is 71-98% for pancreatic masses, 90% for lymph nodes, and 67-92% for submucosal gastrointestinal lesions. Typically, FNA is performed with or without a stylet using a 22 gauge or 25 gauge needle with similar diagnostic accuracy.

When the target lesion is identified, the needle is advanced through the gastrointestinal wall into the lesion under ultrasound guidance. If a stylet is being used, it is removed at this point. A 10 cc syringe under suction is then placed on the end of the needle assembly and the needle is moved back and forth within the lesion to gather cells. The assembly is then removed and the needle contents are expelled onto slides and into preservative media. The stylet is then reinserted and the needle assembly is advanced through the scope for another pass. In the absence of on-site cytopathology, 7 passes with or without a stylet of a solid lesion and 5 passes of lymph nodes with or without a stylet are recommended to achieve high diagnostic accuracy.

EUS-FNA is time consuming, mainly because the stylet needs to be carefully reinserted through the needle prior to each pass. Theoretically, the use of a stylet prevents clogging of the needle with gastrointestinal epithelial cells and mucus which can affect the adequacy of the specimen. However, there are no data to support this. As such there is a variation in practice patterns, with some endosonographers who routinely use a stylet and those that do not. Additionally, those who perform percutaneous FNA frequently do so using needles that do not have a stylet. A recent study suggests that the use of a stylet improves diagnostic accuracy in percutaneous FNA of thyroid lesions. To our knowledge, there have been no studies assessing the use of a stylet on tissue adequacy in EUS-guided FNA.

If the practice of using a stylet during EUS-guided FNA is found to yield the same number of adequate tissue samples as those done without a stylet, then the use of a stylet would be an unnecessary. As stylet replacement is the most time consuming step in FNA, the time of the procedure could be shortened significantly if the stylet is not required.

We propose a randomized controlled trial of EUS guided FNA with and without stylet which will help determine whether the use of a stylet is integral in obtaining adequate tissue aspirates in the diagnosis of solid lesions. To our knowledge, there have been no prospective, randomized studies addressing the effect of the presence or absence of a stylet on specimen adequacy during EUS-guided FNA.


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • patients referred to the Washington University Interventional Endoscopy Division for EUS-guided FNA of a solid lesion (e.g. pancreatic mass, gastric wall mass, or lymphadenopathy)

Exclusion Criteria:

  • Patients <18 years of age
  • patients who cannot provide independent informed consent (i.e. patients with dementia or with a health care proxy)
  • pregnant women (as determined by pregnancy test given as part of standard of care)
  • prisoners
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Please refer to this study by its identifier: NCT01316614

United States, Missouri
Washington University School of Medicine
St. Louis, Missouri, United States, 63110
Sponsors and Collaborators
Washington University School of Medicine
Principal Investigator: Daniel K Mullady, M.D. Washington University School of Medicine
  More Information


Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Washington University School of Medicine Identifier: NCT01316614     History of Changes
Other Study ID Numbers: 201105404
Study First Received: March 14, 2011
Results First Received: November 10, 2014
Last Updated: November 24, 2014

Keywords provided by Washington University School of Medicine:
Fine-Needle Aspiration
Solid Mass
Endoscopic Ultrasound (EUS) processed this record on April 28, 2017