Endoscopic ultrasound‐guided biopsy using a three‐prong asymmetry tip needle for pancreatic tumors and peridigestive tract lesions: Retrospective single‐center study

Endoscopic ultrasound‐guided tissue acquisition is vital for diagnosing pancreatic and peridigestive tract lesions. A new three‐prong asymmetry tip needle has been developed for this procedure. In this study, we retrospectively assessed the diagnostic ability, tissue collection volume, and procedural adverse events of the three‐prong asymmetry tip needle for solid pancreatic, subepithelial, and other organ lesions.


| INTRODUCTION
Endoscopic ultrasound (EUS)-guided tissue acquisition (EUS-TA) is a well-established method for the tissue diagnosis of pancreatic solid lesions and peridigestive tract lesions such as biliary tree, liver, and subepithelial lesions (SELs), and lymph nodes lesions. 1 In pancreatic ductal cancer (PDAC), a definitive tissue diagnosis and collection of adequate tumor-containing tissue are essential for differential diagnosis from other carcinomas or mass-forming benign diseases, preoperative neoadjuvant chemotherapy, and comprehensive genomic profiling (CGP) in personalized medicine. 2,3In addition, specific neoplasms, such as stromal cell tumors, malignant lymphoma, lymph node metastasis of unknown primary origin, and intraabdominal tumors, are difficult to diagnose solely with imaging.Therefore, immunohistochemical staining, morphological examination, and genetic testing are performed, making histological sampling crucial. 4,5ecently, a new type of needle, the EUS-fine needle biopsy (EUS-FNB) needle, has been developed in response to the demand for increased tissue collection volume and sample collection while preserving tissue structure.Various FNB needle tip designs, such as the "reverse bevel" needle, the "Franseen" needle, and the "Fork-tip" needle, have been developed and are used worldwide. 6,7They improve the accuracy of EUS-TA compared to the conventional lancet type, the EUSguided fine needle aspiration (EUS-FNA) needles. 8ore recently, a new needle tip shape, the three-prong asymmetric tip needle (3-PAT needle) (Trident, Micro-Tech Endoscopy, Nanjing, China), was developed and used to improve puncture performance and core tissue collection rates (Figure 1).However, its puncture performance and tissue collection capabilities have not been fully investigated.In this study, we retrospectively examined the tissue collection rate, diagnostic ability, and procedural adverse events (AEs) of EUS-TA using a 3-PAT needle for solid pancreatic lesions, SELs in the digestive tract, and other organ lesions.

| Patients
This retrospective cohort study was conducted to analyze the data of 58 consecutive patients who underwent EUS-TA using the 3-PAT needle between August 2022 and April 2023 at a single territory care center.The inclusion criteria were: (1) age 18 years and older, and (2) EUS-TA conducted with a 3-PAT needle for solid lesions within or in proximity to the gastrointestinal (GI) tract.The exclusion criteria were: (1) patients below 18 years, (2) switch to a different needle due to puncturing difficulty, and (3) patients expressed a desire not to participate in this study.
This study was reviewed and approved by our institutional review board (IRB no.: T2023-0056).Informed consent was obtained from all individual participants included in the study by the opt-out method of our institute website and in-hospital posting (as it was a retrospective study using information contained in medical charts and computerized records).This study was conducted in accordance with the ethical standards of the 1964 Declaration of Helsinki and its subsequent amendments.
2.2 | Novel EUS-TA needle (the 3-PAT needle) The 3-PAT needle is made of a cobalt-chromium alloy, which maintains its shape and sharpness while providing durability, flexibility, and reliable target accessibility.The needle tip is constructed with three very sharp prongs, taking on a trident-like shape, with one prong protruding forward.The single protruding prong improves the puncture capability and, together with the two recessed prongs, is designed to grasp the tissue firmly.In addition, it has a needle-lock system for securely fixing the protrusion distance of the needle with a single touch.This system allows for a quick, strong stroke similar to the door-knocking method and is particularly useful in cases involving hard tumors or lesions with an extended GI wall.

| EUS-TA procedure
The target lesion was visualized from the GI tract using a curved linear-array EUS endoscope (GF-UCT-260; Olympus, Tokyo, Japan).After careful evaluation, including confirmation of the absence of local vascular or other organ involvement, the mass was punctured using The three-prong asymmetry tip needle (3-PAT needle).The 3-PAT needle is made of a cobalt-chromium alloy, which maintains its shape and sharpness while providing durability, flexibility, and reliable target accessibility.The needle tip is constructed with three very sharp prongs, taking on a trident-like shape, with one prong protruding forward.The single protruding prong is designed to improve the puncture capability and, with the two recessed prongs, is designed to grasp the tissue firmly.a 22-or 25-gauge needle.Basically, puncture is performed with 22-gauge needle, but if the lesion is small or difficult to puncture, 25-gauge needle was selected.The stylet was removed, and 20 mL of negative syringe suction was applied at the first puncture.If blood contamination was extensive macroscopically, a slow-pull technique 9 or no suction was applied at the second puncture.The needle was moved to-and-fro within the mass more than 20 times.The obtained tissue specimens were immediately fixed in a 10% neutral-buffered formalin solution for histological examination.The number of passes was decided based on the macroscopically visible core, defined as white or yellow pieces of obtained tissue with an apparent bulk without rapid on-site evaluation (ROSE).Two passes were performed; however, an additional puncture was performed when tissue specimens were insufficient.

| Tissue specimen handling
In this study, only histological analyses were performed without ROSE, macroscopic on-site evaluation and cytology.The fixed tissue specimens were routinely processed and embedded in paraffin in a histological tissue specimen handling room.The paraffin-embedded tissues were cut into 3-μm slices.Only sections that mostly contained tissue specimens were processed into slides.The tissue sections were stained with hematoxylin and eosin for evaluation by a pathologist.Immunohistochemical staining was performed if necessary.

| Outcomes and definitions
The study outcomes included: (1) the tissue collection rate; (2) the accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) in histological diagnosis; (3) the amount of tissue obtained, (4) AEs, and (5) differences between trainee and expert.Tissue collection was defined as whether sufficient tissue was obtained to make a diagnosis.The amount of obtained tissue was assessed using our original quantitative analysis of the scoring system and classified into four phases according to the amount of obtained core tissue, which was defined as an architecturally intact piece of tissue sufficient for histologic evaluation of the targeted lesion; (1) amount of core tissue score 1 indicated no material, (2) amount of core tissue score 2 indicated a tissue fragment or a cell cluster, (3) amount of core tissue score 3 indicated a small histological core tissue; <×10 objective, field diameter = 2.2 mm, (4) amount of core tissue score 4 indicated a large histological core tissue; >×10 objective, filed diameter = 2.2 mm.The amount of blood contamination was classified into three levels; the amount of blood score 1 was little, whereas that of scores 2 and 3 were moderate and high, respectively (Table 1). 10The pathological diagnosis from the surgical specimen was considered the final diagnosis if the patients had undergone surgery for malignant diseases, such as PDAC, pancreatic neuroendocrine neoplasm (PNEN), gastrointestinal stromal tumor (GIST), and hepatic cancer.For patients who did not undergo subsequent surgery, the final diagnosis was made by a combination of histological diagnoses using EUS-TA, clinical diagnosis, and followup with any imaging study for more than 3 months.For benign diseases, such as chronic pancreatitis, serous cyst neoplasms, and leiomyoma, a final diagnosis was made by histological diagnosis from EUS-TA with or without clinical diagnosis using imaging modalities and blood examination with more than 3 months of follow-up.AEs were extracted from all events related to EUS-TA, including abdominal pain, bleeding, perforation, pancreatitis, pancreatic fistulas, and infection, including severity. 11,12A trainee was defined as a physician with less than 5 years EUS-TA procedure experience and an expert was defined as having more than 5 years' experience.

Score Description Number
Amount of core tissue

T A B L E 1
Scoring systems for the amounts of core tissue and blood contamination.

| Statistical analysis
Continuous variables are presented as mean and standard deviations, and categorical variables as frequencies and percentages.Binary variables were compared using Fisher's exact test, and continuous variables were compared using the Mann-Whitney U or Kruskal-Wallis tests.Statistical significance was considered at p < .05.Statistical analysis was performed using SPSS version 29 (IBM Corp., Armonk, NY, USA).).The median number of punctures was 2 (range: 1-3), and the mean lesion diameter was 24.9 ± 12.3 mm.The puncture route was through the esophagus in three cases (5.2%), the stomach in 27 cases (46.6%), and the duodenum in 28 cases (48.3%).A 22-gauge needle was used in 48 patients, and a 25-gauge needle was used in 10 patients.(p = .035),respectively.However, when limited to PDAC, sufficient tissue samples were obtained, and diagnosis was possible in all cases.No significant differences were observed in tissue collection rate or diagnostic performance based on the target organ, puncture route, or lesion size.For the amount of obtained tissue, the mean score for histological core tissue was 3.1 ± 0.8, and the mean score for blood contamination volume was 2.5 ± 0.8 (Table 1).

| Adverse events
Only one of the 58 patients (1.7%) developed a pancreatic fistula of moderate severity as an AE related to the Paraganglioma EUS-FNB needle was significantly higher than that of the FNA needle (81% vs. 87%, respectively, p = .005).In addition, EUS-FNA had an increased mean number of passes compared to FNB (1.6 vs. 2.3, p < .001);however, no significant difference was observed in AE incidence (2.3% vs. 1.8%, p = .64). 17 Furthermore, a meta-analysis on EUS-TA for solid pancreatic tumors using the new generation EUS-FNB needle, the Franssen needle, and Forktip needle, reported that an overall accuracy of 96%, and no significant difference was observed between the two (Franssen needle 97% vs. Fork-tip needle 95%, p = .8). 18 In this study, the diagnostic accuracy of all cases was 89.7%.and the accuracy of EUS-TA performed under similar conditions using other FNB needles at our institution was 94%.Although the number of cases is small compared to other puncture needles, there is no significant difference in the positive diagnosis rate comparing other needles.
The diagnostic accuracy of pancreatic lesions using the 3-PAT needle was 88.6% and was limited to PDAC; it was diagnostic in all cases and comparable to other needles of the new generation.
One of the factors affecting the diagnostic performance of EUS-FNB is the lesion size; the accuracy of lesions >10 mm is 97%, whereas the accuracy of lesions <10 mm is significantly lower, at 64%. 19 The results of this study, in which lesions <10 mm were diagnosed in all cases, suggest that the 3-PAT needle may be suitable for small lesions.Another factor associated with the improved diagnostic accuracy of EUS-TA is ROSE; however, human resources and cost issues limit its use.EUS-FNB can achieve high diagnostic performance without ROSE owing to its large sample volume. 20Reportedly, the next-generation EUS-FNB needles with ROSE are significant predictors of accuracy (odds ratio: 2.60 [95% confidence interval: 1.41-4.79]). 21In this study, we observed an accuracy of 88.6% for pancreatic lesions without ROSE, suggesting that the 3-PAT needle, like other FNB needles, has sufficient diagnostic yield with or without ROSE.
SELs are often discovered incidentally during upper GI endoscopy.Most SELs are benign; however, some tumors such as GIST can become malignant, and an appropriate biopsy specimen is crucial for establishing an accurate diagnosis.Moreover, diagnosis usually involves immunohistochemical analysis, including c-KIT, CD34, and/ or DOG1. 22However, in a previous study, even with the use of jumbo biopsy forceps and the "bite-on-bite biopsy" technique, the diagnostic yield of GI endoscopic biopsy was not high (17%-59%), and bleeding complications were reported in approximately 35% of cases. 23Conversely, EUS-TA has been performed for GIST in recent years with the expectation of high diagnostic performance, and the diagnostic accuracy of EUS-FNA ranged from 60% to 80%. 24A recent meta-analysis showed that the sampling procedure.This patient suffered from a tumor caused by autoimmune pancreatitis in the body of the pancreas and underwent two punctures.A pancreatic fistula with a maximum diameter of 45 mm was located between the posterior wall of the stomach and the body of the pancreas (Figure 2).However, the patient's symptoms improved within 2 weeks of conservative treatment.

| Trainee versus expert
In 28 of 58 patients, the procedures were performed by trainees.Comparing trainees and experts, the accuracy was 88.5% versus 90.6% (p = .790),with no significant difference, and the complication rate were 0% versus 3.1% (p = .367),also with no significant difference.

| DISCUSSION
Diseases that form a mass in the pancreas include malignant conditions such as PDAC, PNEN, acinar cell carcinoma, metastatic pancreatic tumors, solid pseudopapillary neoplasms, and benign conditions such as chronic and autoimmune pancreatitis. 13Differentiating between these conditions is often challenging when using only imaging diagnostics to determine a therapeutic strategy.Additionally, with recent advancements in chemotherapy, the effectiveness of neoadjuvant therapy has been demonstrated in resectable and borderline PDAC cases, and pathological confirmation before surgery has become essential. 14,15EUS-FNA needles have 87%-92% sensitivity and 96%-98% specificity for the pathological diagnosis of solid pancreatic malignancy. 16Subsequently, EUS-FNB needles with various tip structures have been developed to achieve greater tissue volume and structural preservation for a more accurate pathological diagnosis (Table 4).A meta-analysis of reports from randomized controlled trials (RCTs) comparing EUS-FNA and EUS-FNB needles revealed that the diagnostic accuracy of the T A B L E 3 (Continued) capacity of FNB (94.9%) was higher than that of FNA (80.6%), and this trend was further increased when ROSE was added. 25Although a small sample size was used in this study and we did not include patients with GIST, the diagnostic rate of the 3-PAT needle for SELs was 100% (7/7), indicating that this needle is useful for SELs.Other organs indicated for EUS-TA include the lymph nodes, liver, biliary tree, and the abdominal (retroperitoneal) cavity.EUS-TA is performed on lesions in these areas when the pathological diagnosis may affect the patient's therapeutic management or when other examination methods are infeasible or undiagnostic.With regard to the liver, EUS-TA is used to diagnose liver masses and evaluate chronic liver disease and is reportedly safer than conventional percutaneous methods. 26The usefulness of EUS-TA for lymph nodes has been demonstrated, especially with the new-generation EUS-FNB needles; they show higher accuracy than the conventional EUS-FNA needles, and the number of punctures can be reduced. 27The accuracy of EUS-FNB for peritoneal lesions has been reported as 66.7%, sensitivity as 63.6%, and specificity as 100%, indicating that it is a valuable tool for patients with difficult-to-diagnose peritoneal diseases. 28In the present study, EUS-TA was performed for four lymph nodes, two retroperitoneal tumors, and one liver mass, and the diagnostic accuracy was as high as 80% without any AE, demonstrating the efficacy and safety of the 3-PAT needle in other organs and lesions besides the pancreas and SELs.
In EUS-TA, simply obtaining a large sample volume is insufficient.Particularly in CGP for precision medicine for all cancers, diagnosis is affected by the surface area of the sample and the tumor cell ratio.In a representative CGP, FoundationOne CDx (F1CDx; Foundation Medicine, Cambridge, MA, USA), a proper sample has a specimen surface area of ≥25 mm 2 and a tumor cell ratio of ≥20%.Therefore, future EUS-TA procedures will require more viable tumor tissues and less contamination with blood and interstitial components.We evaluated the obtained tissues by classifying the core tissue amount into four levels and the amount of blood contamination into three levels.In our previous reports where we used this same scoring system to assess the sample volume and blood contamination, the core tissue amounts were 2.2 ± 0.5 for the conventional 22-gauge FNA needle (Expect, Boston Scientific, Natick, MA, USA and EZshot3, Tokyo, Japan, Olympus), 3.3 ± 0.5 for the 22-gauge Franseen needle (Acquire, Boston Scientific), and 3.8 ± 0.2 for the 20-gauge reverse bevel needle (ProCore, Wilson Cook Medical Inc., Bloomington, Indiana, USA.).Moreover, a comparison of the presence or absence of aspiration showed that the average core tissue score of EUS-TA with aspiration was significantly higher (3.0 ± 0.5 vs. 1.3 ± 0.4, p = .03)with the conventional 22-gauge needle; however, the average blood score was equivalent (1.5 ± 0.3 vs. 1.1 ± 0.2, p = .130).In contrast, with the Acquire 22-gauge needle and ProCore 20-gauge needle, no significant difference was observed in the average core tissue scores between EUS-TA with and without aspiration (3.7 ± 0.4 vs. 3.5 ± 0.4, p = .734);however, blood contamination increased (2.3 ± 0.7 vs. 1.6 ± 0.3, p = .061). 10 In this study, EUS-FNB was mostly performed with aspiration, resulting in a core tissue score of 3.1 ± 0.8 and a blood contamination score of 2.5 ± 0.8.Compared with other FNB needles, the 3-PAT needle had a comparable tissue score but a higher blood contamination score.In the future, non-aspiration methods should be performed using a 3-PAT needle.To date, the only reported study on the 3-PAT needle was a single referral center RCT that compared the 22-gauge 3-PAT needle with the Franseen needle for pancreaticobiliary neoplasms.This study concluded that the diagnostic ability of the 3-PAT and Franseen needles did not significantly differ, although the Franseen needle demonstrated higher cellularity (p < .001). 29Es in EUS-TA occur at a rate of 2.1% (246/11652), among which pancreatic fistula is extremely rare, occurring at a rate of 0.008% (1/11652) in previous reports. 11In this study, a pancreatic fistula of moderate severity was observed in only one case out of 58 (1.7%).It developed due to the double puncturing of a mass caused by autoimmune pancreatitis in the body of the pancreas.However, the condition improved rapidly within 2 weeks without any interventional therapy, and was therefore likely due to a temporary leakage of pancreatic fluid caused by damage to the thin pancreatic ducts, such as the branch duct.The novel puncture needle is safe and effective, with no difference between trainee and expert in both accuracy and complication rates.
To the best of our knowledge, this is the first study to examine the efficacy of EUS-TA with the 3-PAT needle for pancreatic disease, SELs, and other organ lesions.However, it had several limitations.First, it was a retrospective study conducted at a single facility without a comparison group.In addition, the occurrence of SELs and other organ lesions was limited.Finally, fewer cases with 25-gauge needles were included, and we did not employ any 19-gauge needles.In the future, RCTs with larger sample sizes and comparisons of other new-generation EUS-FNB needles, various needle sizes, and other puncture techniques will be desirable.

F I G U R E 2
Pancreatic fistula after an endoscopic tissue acquisition procedure.Computed tomography showed fluid retention with a maximum diameter of 45 mm located between the posterior wall of the stomach and body of the pancreas.The patient was diagnosed with a pancreatic fistula after the endoscopic tissue acquisition procedure.The white arrows indicate fluid retention located between the posterior wall of the stomach and the body of the pancreas.T A B L E 4 Puncture needle characteristics.chromium: 19, 22, 25G Three-prong asymmetric tip needle, taking on a trident-like shape with one prong protruding forward One-button adjusters for needle depth and sheath length provide easy and precise one-hand control SharkCore Medtronic Stainless: 19G, Nitinol: 22, 25G Forked tip with two sharp points of different lengths and a multifaceted bevel with six cutting surfaces Dial-style needle stopper Top-gain Medi-Globe Nitinol: 19, 22, 25G Flanged type 3-point needle tip design with a crown Twist-lock for one-hand operation ProCore Cook Medical Nitinol: 19, 20, 22, 25G 19, 22, 25G: Reverse bevel, 20G: Forward facing bevel Dial-style needle stopper G, gauge

Table 2
shows the patient characteristics.A total of 58 patients were included in this study comprising 41 men and 17 women; their mean age was 66.2 ± 14.4 years.The target lesions were pancreatic lesions in 44 cases, SELs in seven cases, lymph node lesions in four cases, retroperitoneal tumors in two cases, and a liver mass in one case.The final diagnoses were benign disorders in 17 patients (29.3%) and malignancies in 41 cases (70.7%

Table 3
Patient characteristics.
T A B L E 2 Puncture results.
T A B L E 2 (Continued)T A B L E 3Abbreviations: NA, not available; NPV, negative predictive value; PPV, positive predictive value.