Stylet Slow-Pull Technique Compared To Standard Suction For Endoscopic Ultrasound-Guided Fine-Needle Biopsy In Pancreatic Solid Lesions: Data From A National Multicenter Randomized Trial
Phase: NA
Conditions: Pancreatic Solid Lesions
Sponsor: ARNAS Civico Di Cristina Benfratelli Hospital

COVER PAGE 
OFFICIAL TITLE OF THE STUDY  
Stylet Slow-Pull Technique Compared To Standard Suction For Endoscopic Ultrasound-Guided 
Fine-Needle Biopsy In Pancreatic Solid Lesions: Data From A National Multicenter Randomized 
Trial. 
 
LAST APPROVED VERSION OF THE PROTOCOL  
Last approved version of the current protocol was of 14 September 2015. 
 
NCT NUMBER 
NCT number not available. 
 
DATE OF THE DOCUMENT 
The date of the current document is 22 February 2019. 
 
 

INTRODUCTION 
 
Since its introduction 27 years ago, endoscopic ultrasound-guided fine needle aspiration 
(EUS-FNA) has revolutionized the diagnostic approach to pancreatic masses and has become the 
first diagnostic test to establish a correct diagnosis in patients with suspicious pancreatic solid 
lesion. EUS-FNA represents now the standard of care for the pathological diagnosis of solid 
pancreatic masses, and has a sensitivity and a specificity of 85%–89% and 96%–99%, respectively. 
Needles of different size have been used, ranging from 19 Gauge to 25 Gauge, despite the strongest 
evidences is for the 22 and the 25 Gauge needles. The availability of rapid on-site evaluation 
(ROSE) to assess specimens’ adequacy by a cytopathologist during EUS-FNA improves diagnostic 
accuracy of about 10 to 15%, but high costs and the lack of availability of ROSE in many centers, 
even the referral ones, have limited the widespread utilization of the EUS-FNA procedures. For 
these reasons in recent years, new needles have been designed (i.e. cutting tip or a side-slot in the 
distal portion of the needle) to obtain samples suitable for histological evaluation (endoscopic 
ultrasound-guided fine needle biopsy [EUS-FNB]). These new needles allow the macroscopic on-
site evaluation (MOSE) of the quality of samples by the endoscopist, who can decide whether or not 
to perform additional biopsies. Various EUS-FNA techniques have been described, but the correct 
methods remain debatabl. Most of the studies have compared EUS-FNA with standard suction (10-
20 ml negative suction pressure) versus the  “slow-pull” EUS-FNA technique (pulling the stylet 
while moving the needle within the lesion), but final results were conflicting and ranged from clear 
advantage of the slow-pull approach to no difference between the two techniques. In the studies that 
showed advantages of the slow-pull technique, most of the gain was related to a significant decrease 
of the bloodiness of the specimens, which made the cytological reading easier to be accomplished 
as compared to more bloody specimens obtained with the suction technique. The interference of 
bloodiness with the cytological evaluation is a well-known phenomenon. On the other hand, data on 
the amount of blood gathered during EUS-FNB performed using the two different techniques and 
its interference with the performance of both slow pull and standard suction techniques in patients 
with pancreatic solid lesions are limited. The aim was to design a randomized controlled study to 
compare the amount of bloodiness of the specimens acquired by the slow-pull technique with those 
gathered by using the standard suction technique during EUS-FNB in patients with solid pancreatic 
masses. Secondary aims were the effect of blooding on the performance of the two techniques with 
regards to sensitivity, specificity, and diagnostic accuracy. 
 

Materials and methods 
 
A Randomized, multicenter study comparing the slow-pull technique with the standard 
suction technique during EUS-FNB in patients with pancreatic solid lesions. The study involved 
three referral centers for pancreatico-biliary diseases: the Gastroenterology and Endoscopy Unit. 
ARNAS Civico-Di Cristina-Benfratelli Hospital, Palermo, Italy; the Gastroenterology and 
Endoscopy Unit. Marche Polytechnic University, Ospedale A. Murri, Fermo, Italy; the 
Gastroenterology Unit. AUSL Bologna, Bellaria-Maggiore, Bologna, Italy.  
 
The protocol was approved by the institutional medical ethical committee at each 
participating institution and written informed consent was obtained from all patients for 
participation in the study.  
 
All consecutive patients with a newly diagnosed pancreatic solid lesions suitable for EUS-
guided tissue acquisition were considered for enrollment. Inclusion criteria were: age >18 years old; 
solid pancreatic lesion on imaging MRI and/or CT-scan referred for tissue acquisition; lesion that 
can be visualized with EUS and needle puncturing can be technically feasible; able to sign informed 
consent. Patients were excluded in the presence of at least one following criteria: <18 years-old, 
pancreatic cystic lesions, extra-pancreatic lesions or inaccessible/non-visualizable lesions, previous 
gastrectomy, international normalized ratio > 1.5, impossibility to suspend anticoagulant therapy, 
platelet count < 50.000 cells/cubic millimeter, severe or unstable clinical conditions that 
contraindicated EUS procedure, pregnancy, inability to give informed consent, and refusal to 
participate to the study. Written informed consent was obtained from all patients before the 
procedure.  
 
All the EUS procedures were carried out by A skilled endosonographer with the patients 
under conscious sedation or deep sedation according to the anesthesiological guidelines approved in 
each participating center. All EUS-FNB were done using a 20 Gauge needle (EchoTip ProCore 20G 
with ReCoil Stylet™, Cook Medical, Bloomington, IN, USA). The ReCoil Stylet´s has an 
automatic recoiling capability designed to help users to manage more easily the stylet, thus 
minimising the risk of contamination. Before puncturing, color doppler examination was performed 
to exclude the presence of interposing vessels. The needle tip was sharpened by withdrawing the 
stylet of approximately 2 mm, and then it was advanced into the lesion under real-time EUS 
guidance. In patients randomized to the stylet slow-pull techniques, 15 to-and-fro movements 
within the lesion were performed while gently pulling the needle stylet slowly and continuously 
upwards. In patients randomized to the standard suction technique, 15 to-and-fro movements within 

the lesion were performed using a 10-mL suction syringe. In both sampling procedures the fanning 
technique was used to maximized sample acquisition. Tissue samples were expelled onto slides by 
reinserting the stylet and the visible core was physically lifted off the slides placing it into a 
formalin vial for histological evaluation. For the macroscopic adequacy, the endosonographer 
evaluated for the presence of a visible core defined as a worm-like material whitish/yellowish or 
red, not including fluid-like specimens in the formalin vial, which was judged to be adequate to 
perform a pathological analysis. The pathologists were “blinded” on which group the vials received 
were belonging to.  
 
Randomization was performed using random sequences generated by a computer and then 
closed in consecutive numbered envelopes. 
 
Data on patients’ and lesions’ characteristics, degree of the blood contamination of the 
specimen, sensitivity, specificity and diagnostic accuracy of the two techniques; adverse events 
related to the procedures were collected and entered in an electronic database in order to carry out 
the final statistical analysis.  
 
Outcome measures 
 
The primary end point of the study was the degree of blood contamination of the collected 
specimens in patients with pancreatic solid lesions who underwent EUS-FNB using the 20Gauge 
Procore Needle and the slow pulling or the standard aspiration techniques. Secondary outcomes 
were technical success, comparison of the performance of the two techniques during EUS-FNB in 
terms of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), 
and diagnostic accuracy, and occurrence of adverse events. 
 
Outcome Definitions 
 
The degree of blood contamination of the specimen was based on the pathologist evaluation 
of the formalin fixed and paraffin embedded (FFPE) tissue samples and defined as significant when 
a large amount of blood cells made pathological diagnosis difficult to be made. On the other hand, 
blood contamination of the specimen was defined as not significant when no or only few blood cells 
were present without any influence on the pathological diagnosis. 

 
Sensitivity was defined as the true positive rate whereby the test was the final cytologic 
diagnosis, Specificity as the true negative rate (proportion of actual negatives that are correctly 
identified as such), PPV was defined as the number of true positive divided the number of positive 
calls (true positive and false positive),  NPV was defined as the number of true negative divided the 
number of negative calls (true negative and false negative). Diagnostic accuracy was defined as the 
ratio between the sum of true positive and true negative values divided by the total number of 
masses.   
 
 
Technical success was defined as the capability of sampling the target lesion associated with 
the presence of a visible core, according to endosonographer’s judgment, potentially useful for the 
final pathological analysis. 
 
Adverse events were defined based on the criteria expressed by Cotton et al. [Cotton PB. 
Gastrointest Endosc 2010;71:446-54] 
Samples positive for malignancy were considered diagnostic for malignancy, while in 
patients with negative EUS-FNB, surgical specimen evaluation, results of other diagnostic 
investigations and/or a clinical follow-up of at least 6 months were used to establish the definitive 
diagnosis. 
 
Statistical Analysis  
 
The sample size was calculated based on the results of a previous study [Nakai Y. Dig Dis 
Sci. 2014;59:1578-85] that showed that blood contamination of the specimen was lower with the 
stylet slow-pull technique as compared with the standard suction technique (25% vs 70%), with a 
consequent increase in the diagnostic accuracy.  Based on these data we calculated for a difference 
of 25%, at a power of 80% and an alpha of 0.05 (two-sided test), a final sample size of 110 patients 
(55 patients in each group).  Continuous variables will be reported as mean ± standard deviation 
(SD). Categorical variables will be presented as numbers and percentage and will be compared 
either using the chi-square test (with Yates’ correction when appropriate) or Fisher exact test.  
 
Statistical was conducted using the Fisher’s exact test for categorical variables and the 
Mann–Whitney U-test for continuous variables. Sensitivity, specificity, positive predictive value 
(PPV), negative predictive value (NPV), and overall diagnostic accuracy for each arm were 
investigated by comparing the results with the definitive diagnosis. Statistical tests were considered 

significant at a corresponding p value of <0.05. Data handling and analyses were done with SPSS 
14. 
 
RESULTS  
 
From May 2017 to May 2018, a total of 182 consecutive patients were screened for 
participation in this study, of whom 72 were excluded, while 110 patients constituted the study 
cohort and were randomized to one of two groups: stylet slow-pull technique (55 patients) and 
standard suction technique (55 patients) as showed in  figure 1. Overall, there were 49 male (44.5%) 
and 61 female (55.5%), with a mean age of 70.9±11.3 years. Patients’ and lesions’ characteristics 
are shown in Table 1 and appeared similar in both groups. The majority of lesions were located in 
the head of the pancreas (72 lesions corresponding to 65.5%) with similar rates in slow-pull group 
(69%) and in the standard suction group (62%). No difference in mean size of the lesions was found 
between the two groups(35.9±19.9 vs 37.6± 14.1 cm; p=ns). 
 
Technical success was achieved in 95% of patients (slow pull technique 96% vs standard 
suction technique 94%, p=ns) with a not-significant blood contamination of the specimen in 85 
patients (overall 77.3%: slow-pull 80% vs standard suction 74%, p=ns). A diagnosis of malignancy 
was obtained in 98 cases as showed in Table 2. Fifty were in the slow-pull group and 48 in the 
standard suction group. In 6 patients (1 in the slow-pull and 5 in the standard suction group) with a 
benign histological diagnosis at EUS-FNB the definitive diagnosis was chronic pancreatitis. Thus, 
these patients were considered true negative. Finally there were 6 false negative cases (4 in the slow 
pull technique group and 2 in standard suction group). Comparing the two groups (Table 3), the 
sensitivity, specificity, negative likelihood ratio, positive likelihood ratio, and diagnostic accuracy 
were  96 vs 93%, 100% vs 100%, 0.04 vs 0.07, “infinity” in both, and 96 vs 93%, respectively 
without any statistical difference between them. No procedure-related adverse events were observed 
in the two groups.