Diagnostic Accuracy of FNA (Fine Needle Aspiration) on Solid Pancreatic Lesions: is Aspiration- Related?
EUS-FNA has a central role in the diagnostic algorithm of solid pancreatic masses [ASGE
Practice Committee] with high sensitivity and specificity (75-92% - 82-100%), [1-2-3] and
low complication rate (1-2%) [4-5-6]. In the clinical setting of solid pancreatic mass a
histological diagnosis appears highly relevant both for differential diagnosis
(adenocarcinoma, lymphoma or neuroendocrine tumour) and for optimal therapeutic decision.
For the cythopathologic diagnosis of pancreatic cancer, sensitivity increased with the
operator's experience and reached 80% after 20 to 30 EUS-FNA. Furthermore it well
demonstrated that on-site cytopathology interpretation during the procedure increase the
diagnostic yield of EUS-FNA [7-8]. ROSE (Rapid On -Site Evaluation) may be useful to guide
the number of FNA passes, learn which parts of the lesion may be targeted for increased
diagnostic yield, and correct technical errors (e. g. bloody or paucicellular material) [9,
10]. The diagnostic yield of EUS-guided biopsies depends on size, location and
characteristics of target tissues as well as on technical and procedural factors (type of
needle, biopsy technique and material processing) [11-20].
Expertise and training of endosonographer and interaction with the cytopathologist have also
an important role [7-14-15]. Up to now three different sizes of needle are available for
collecting cytological material: 25 - 22 and 19 gauge with an aspiration volume syringe of
10ml. Most of the studies on EUS-FNA have been conducted using 22G needles. Data on thinner
(25G) or larger (19G) needles are limited. A number of recent studies, including two RCTs,
compared results obtained with needles of various diameters. All these studies were
performed in the setting of pancreatic masses [18-20]. Although thinner needles provide less
cellular material than do larger needles, the specimens from the former are less
contaminated by blood, and thus easier to interpret. In addition, thinner needles may be
easier to use because of greater flexibility, particularly for locations requiring important
scope bending [18, 19]. An RCT in 131 patients found no significant differences between 22G
and 25G needles in terms of diagnostic yield for malignancy . Finally another RCT
compared EUS-FNA without ROSE using 19G or 22G needles in 117 patients  showed a similar
diagnostic accuracy for both needles.
If the diameter of the needle used does not appear to affect the diagnostic accuracy of FNA
on solid pancreatic lesions, preliminary studies show that using suction during EUS FNA of
solid masses is associated with a significantly higher sensitivity for cancer diagnosis (86%
vs. 67%; P=0.05) . A pilot trial suggested that applying continuous high pressure
suction (using a balloon inflation device) allowed retrieval of tissue samples for
histopathological examination in most cases .
A new needle Expect by Boston Scientific are available with an aspiration syringe with
variable volume of 5-10-15-20cc. No studies were performed comparing the diagnostic yield of
FNA on solid pancreatic masses performed with different aspiration volume (10 and 20ml) and
The aims of our prospective study are to compare EUS-FNA in the same solid pancreatic mass
performed with the 22 gauge needle with aspiration volume syringe of 10ml, 20ml and without
aspiration, looking for: sample adequacy, diagnostic accuracy, complications.
Patients This was a prospective clinical study at four referral center for EUS: ISMETT/UPMC
(Mediterranean Institute for Transplantation and Advanced Specialized Therapies/University
of Pittsburgh Medical Center in Italy), Palermo; AUSL Bologna, Bellaria-Maggiore Hospital;
Civico-A.R.N.A.S. Hospital, Palermo; Humanitas IRCCS, Rozzano, Milano. We planned to collect
at least 100 cases in 3 months. The study protocol conforms to the ethical guidelines of the
1975 Declaration of Helsinki (6th revision, 2008) as reflected in a priori approval by the
institution's human research committees.
The inclusion criteria for the study were: diagnosed or suspected solid pancreatic lesions
according to imaging (CT-scan or/and MRI); no contraindications for FNA (see exclusion
criteria). The exclusion criteria were: age < 18 years; cystic pancreatic lesions; history
of previous gastrectomy; patients hemodynamically unstable or with severe coagulopathy
(international normalized ratio [INR] > 1.5 or platelet count < 60.000 cells/cubic
millimetre [cmm3]); patients unable to suspend anticoagulant therapy; pregnancy; inability
to give informed consent; refusal to participate to the study.
Data on comorbidity and chronic treatment were recorded as well as data on possible
complications related to the procedure. Patients undergoing anticoagulant or antiaggregant
therapy for noncritical problems discontinued the treatment at least 5 days before the
endoscopic procedure or until INR normalization, starting low dose heparin. Written informed
consent was obtained from all patients for the procedures performed. All procedures were
performed under conscious sedation with meperidine ± midazolam or deep sedation with
propofol according to each center guideline and patient clinical condition.
Procedure Endoscopic ultrasonography was performed using a linear echo-endoscope by five
experienced echo-endoscopist with a current case volume of at list 500 per year (200 FNA).
The standard technique for FNA was adopted: the needle is advanced under real-time EUS
guidance into the target lesion by using a quick, strong thrust of the handle. The stylet is
completely withdrawn and a syringe attached to the end of the needle device. Once inside the
lesion, after applying negative pressure suction by opening the lock device of the syringe,
the needle is moved back and forth 15 times under EUS guidance. The suction syringe is then
released, the needle withdrawn into the catheter, and the whole system removed from the
The needle system was in all cases the 22 gauge EUS-FNA (Expect needle). After the puncture
the stylet was removed, and we performed three punctures with a 22 G needle with both volume
aspiration 10 and 20 cc and without syringe for each lesion. The sequence (10cc, 20cc, no
aspiration) was randomly assigned by sealed envelope system.
Technical success was defined as puncturing the target tissue properly without technical
difficulties (inability of the needle to exit from the channel of the scope) or mechanical
rupture and obtaining some visible tissue specimens or fragments with each puncture.
Tissue samples was immediately smeared into slides after each puncture, fixed and all the
prepared slides will be viewed by experienced pathologists for ROSE (Rapid On Site
Evaluation). For each pass, after smearing sample into the slides, the material was fixed in
formalin for cyto histological evaluation. The cytopathologist was always blinded as to
which aspiration was used for which specimen.
The cases will be stratified into 4 diagnostic categories applied for ROSE and for
a) Positive for malignancy, b) Suspicious for malignancy, c) Negative for malignancy, d) Non
For each aspiration two fundamental parameters will be evaluated on slides and formalin
fixed sample: sample adequacy intended as overall cellularity (including normal, neoplastic,
non-epithelial cells) and diagnostic accuracy.
Post-procedural follow-up After EUS-FNA the patients were monitored for at least six hour to
detect immediately post-procedural complication and were followed up with a scheduled
protocol during the 30 days post-procedure in order to evaluate clinical status, blood
chemistry, and to detect late complications. All patients were followed up for at least 1
month. All adverse events were evaluated and related or not to the procedure. All data were
recorded electronically on excel database for the final analysis.
STATISTICAL ANALYSIS Data were analyzed using the SPSS 15 software package (SPSS Inc.,
Chicago, Illinois, USA). Continuous variables were summarized as means ± SD, or range, when
appropriate. Categorical variables were summarized as frequency and percentage. For
comparison of qualitative variables, a chi-squared test was calculated. For comparison of
quantitative variables, Students t test was used. Sensitivity, specificity, positive
predictive value (PPV), negative predictive value (NPV), and overall accuracy for each arm
was investigated. Differences were considered significant at a P value of <0.05
Endpoint Classification: Efficacy Study, Intervention Model: Single Group Assignment, Masking: Single Blind (Investigator), Primary Purpose: Diagnostic
Tissue samples was immediately smeared into slides after each puncture, fixed and all the prepared slides will be viewed by experienced pathologists for ROSE (Rapid On Site Evaluation). For each pass, after smearing sample into the slides, the material was fixed in formalin for cyto histological evaluation. The cytopathologist was always blinded as to which aspiration was used for which specimen.
Ilaria tarantino, MD
The Mediterranean Institute for Transplantation and Advanced Specialized Therapies
Italy: Ethics Committee