Trial Information

A Randomized Controlled Trial Of Endoscopic Ultrasound-Guided Fine-Needle Aspiration With And Without A Stylet : A Pilot Study

Various techniques have been described to optimize accuracy, efficiency, and quality of
EUS-FNA specimens. FNA is typically performed using a 22- or 25-gauge needle with a stylet
under EUS guidance. The lesion is punctured with a stylet in place or slightly withdrawing
the needle. After puncture, the stylet is pushed out of the needle tip and then the needle
is moved to and fro within the lesion and this process is repeated for each needle pass. It
is currently believed that the use of a stylet for EUS-FNA helps prevent clogging of the
needle by gut wall tissue, which could limit the ability to aspirate cells from the target
lesion. This may improve the quality of specimens and hence enhance the diagnostic yield of
specimens obtained. This is a logical assumption, but there are no data demonstrating
clearly that the use of a stylet increases the yield of EUS-FNA. At the present time, it is
recommended that the stylet is re-inserted back into the needle prior to each FNA pass. The
use of a stylet during EUS-FNA is cumbersome, time and energy consuming and increases the
costs of EUS-FNA needle systems. In some circumstances, the stylet may actually make EUS-FNA
very difficult as it may be impossible to advance or remove the stylet once the target has
been punctured. This tends to occur when the echoendoscope or the needle is bent and a large
(19 gauge) needle is being used. In addition, the data comparing the effectiveness of
EUS-FNA with stylet to FNA without stylet is limited. Paquin et al compared the adequacy,
the bloodiness, and the yield of FNA samples obtained with a stylet to FNA without a stylet.
In this study, the use of stylet for EUS-FNA was associated with a reduced specimen adequacy
and more bloody passes. 13 Thus the use of a stylet for EUS-FNA is questionable and needs
further investigation. If the diagnostic yield, adequacy and quality of specimens obtained
by EUS-FNA without a stylet is found to be equivalent to that with a stylet, this could
potentially make a strong case for not using a stylet and thus making the procedure easier,
more time- and cost-efficient. The hypothesis and specific aims of this prospective
randomized controlled trial are as follows:

First hypothesis: There is no difference in the degree of cellularity, contamination, and
amount of blood in samples obtained by EUS-FNA with and without a stylet Specific Aim #1: To
compare the degree of cellularity, contamination, and amount of blood in samples obtained by
EUS-FNA with and without a stylet

Second hypothesis: There is no difference in the diagnostic yield of malignancy in specimens
obtained by EUS-FNA with a stylet compared with EUS-FNA without a stylet.

Specific Aim #2: To compare the diagnostic yield of malignancy in specimens obtained by
EUS-FNA with and without a stylet.

Third hypothesis: An acceptable level of inter-observer agreement exists among
cytopathologists in the assessment of specimens obtained from EUS-FNA with stylet and
EUS-FNA without a stylet.

Specific Aim #3: To assess the inter-observer agreement among cytopathologists in the
evaluation of specimens obtained from EUS-FNA with stylet and specimens obtained from
EUS-FNA without a stylet.