The role of endoscopic ultrasonography in the diagnosis and management of pancreatic cancer

Diagnostic Endoscopic Ultrasound in Pancreatology: Focus on Normal Variants and Pancreatic Masses

Background

Endoscopic ultrasound (EUS) is a main tool in gastroenterology for both diagnosis and exclusion of pancreatic pathology. It allows minimally invasive assessment of various diseases or anatomic variations affecting the pancreas also with the help of new Doppler technologies, elastography, contrast-enhanced imaging including post hoc image processing with quantification analyses, three-dimensional reconstruction, and artificial intelligence. EUS also allows interventional direct access to the pancreatic parenchyma and the retroperitoneal space, to the pancreatic duct, pancreatic masses, cysts, and vascular structures.

Summary

This review aimed to summarize new developments of EUS in the field of pancreatology. We highlight the role of EUS in evaluating pancreatic pathology by describing normal anatomic variants like pancreas divisum, pancreatic lipomatosis, pancreatic fibrosis in the elderly and characterizing pancreatic masses, both in the context of chronic pancreatitis and within healthy pancreatic parenchyma. EUS is considered the optimal imaging modality for pancreatic masses of uncertain dignity and allows both cytological diagnosis and histology, which is essential not only for neoplastic conditions but also for tailoring therapy for benign inflammatory conditions.

Key Messages

EUS plays an indispensable role in pancreatology and the development of new diagnostic and interventional approaches to the retroperitoneal space and the pancreas exponentially increased over the last years. The development of computer-aided diagnosis and artificial intelligence algorithms hold the potential to overcome the obstacles associated with interobserver variability and will most likely support decision-making in the management of pancreatic disease.

A Unicorn Disease: The Large Duct Variant of Invasive Ductal Adenocarcinoma of the Pancreas

Large duct adenocarcinoma (LDA) is a rare histopathological variant of pancreatic ductal adenocarcinoma (PDAC) that closely mimics intraductal papillary mucinous neoplasm (IPMN). We present a 74-year-old female diagnosed with LDA in 2017. She was initially managed with chemotherapy and laparoscopic distal pancreatectomy. After five years of stable disease on systemic chemotherapy, she was referred to us to explore further definitive treatments. We used a multidisciplinary approach with curative-intent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC), followed by oral maintenance chemotherapy. Subsequent scans showed stable disease; she eventually underwent neoadjuvant radiation and surgery with intraoperative radiation therapy (IORT) and achieved remission.

Current Practice Patterns of Endoscopic Ultrasound-Guided Tissue Sampling for Pancreatic Solid Mass in Korea: Outcomes of a National Survey

Background/Aims

Although endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) and fine needle biopsy (FNB) are widely used for tissue acquisition of pancreatic solid mass, the optimal strategy of this procedure has not been established yet. The aim of this nationwide study was to investigate the current practice patterns of EUS-FNA/FNB for pancreatic solid mass in Korea.

Methods

The Policy-Quality Management of the Korean Pancreatobiliary Association (KPBA) developed a questionnaire containing 22 questions. An electronic survey consisting of the questionnaire was distributed by e-mail to members registered to the KPBA.

Results

A total of 101 respondents completed the survey. Eighty respondents (79.2%) performed preoperative EUS-FNA/FNB for operable pancreatic solid mass. Acquire needles (60.4%) were used the most, followed by ProCore needles (47.5%). In terms of need size, most respondents (>80%) preferred 22-gauge needles regardless of the location of the mass. Negative suction with a 10-mL syringe (71.3%) as sampling technique was followed by stylet slow-pull (41.6%). More than three needle passes for EUS-FNA/FNB was performed by most respondents (>80%). The frequency of requiring repeated procedure was significantly higher in respondents with a low individual volume (<5 per month, p=0.001). Prophylactic antibiotics were routinely used in 39 respondents (38.6%); rapid on-site pathologic evaluation was used in 6.1%.

Conclusions

According to this survey, practices of EUS-FNA/FNB for pancreatic solid mass varied substantially, some of which differed considerably from the recommendations present in existing guidelines. These results suggest that the development of evidence-based quality guidelines fitting Korean clinical practice is needed to establish the optimal strategy for this procedure.

Macroscopic on-site evaluation (MOSE) of specimens from solid lesions acquired during EUS-FNB: multicenter study and comparison between needle gauges

Background and study aims  The standard method for obtaining samples during endoscopic ultrasonography (EUS) is fine-needle aspiration (FNA), the accuracy of which can be affected by the presence of a cytopathologist in endoscopy room (rapid on-site evaluation [ROSE]). With the introduction of fine-needle biopsy (FNB), macroscopic on-site evaluation (MOSE) of a acquired specimen has been proposed. Only a few studies have evaluated the role of MOSE and in all except one, a 19G needle was used. Our primary aim was to evaluate the diagnostic yield and accuracy of MOSE with different needle sizes and the secondary aim was to identify factors influencing the yield of MOSE. Patients and methods  Data from patients who underwent EUS-FNB for solid lesions, with MOSE evaluation of the specimen, were collected in six endoscopic referral centers. Results  A total of 378 patients (145 F and 233 M) were enrolled. Needles sizes used during the procedures were 20G (42 %), 22G (45 %), and 25G (13 %). The median number of needle passes was two (IQR 2-3). The overall diagnostic yield of MOSE was of 90 % (confidence interval [CI] 86 %-92 %). On multivariable logistic regression analysis, variables independently associated with the diagnostic yield of MOSE were a larger needle diameter (20G vs. 25G, OR 11.64, 95 %CI 3.5-38.71; 22G vs. 25G, OR 6.20, 95 %CI 2.41-15.90) and three of more needle passes (OR 3.39, 95 %CI 1.38-8.31). Conclusions  MOSE showed high diagnostic yield and accuracy. Its yield was further increased if performed with a large size FNB needles and more than two passes.

The role of EUS in diagnosing focal autoimmune pancreatitis and differentiating it from pancreatic cancer

Background and Objectives:

The clinical presentation of focal autoimmune pancreatitis (FAIP) and together with radiological overlap can mimic pancreatic cancer (PC). The aim of this study is to construct and validate a prediction model for differentiating FAIP from PC according to EUS characteristics.

Patients and Methods:

Ninety patients with FAIP and 196 patients with PC, who consecutively underwent EUS at our center from January 2013 to December 2018, were retrospectively included in the study. The enrolled patients were randomly divided into either a derivation sample or a validation sample. According to EUS characteristics, multivariate stepwise logistic regression and receiver operating characteristics (ROC) analyses were used to construct a prediction model in derivation sample, and then, the efficacy was assessed in validation sample.

Results:

EUS characteristics that were suggestive of FAIP included diffuse hypoechogenicity, hyperechoic foci/stands or lobularity (parenchymal heterogeneity), bile duct wall thickening and peripancreatic hypoechoic margin; and EUS features favoring PC included focal hypoechogenicity, absence of parenchymal heterogeneity, pancreatic duct dilation, and vessel involvement. The prediction model, with an area under the ROC curve of more than 0.95, had a good capability to distinguish FAIP from PC. By using the optimal cutoff value, the efficacy of model for diagnosing PC showed 83.7%–91.8% sensitivity and 93.3%–95.6% specificity.

Conclusions:

It is feasible to differentiate FAIP from PC based on EUS characteristics. The prediction model built in this study needs to be further confirmed by multicenter prospective researches.

Diagnostic Fine-Needle Biopsy of Small Solid Pancreatic Lesions Using a Franseen Needle during Endoscopic Ultrasound Examination

BACKGROUND AND AIM

During endoscopic ultrasound-guided fine needle aspiration biopsy (EUS-FNB), Franseen needles can help collect sufficient tissue to permit histopathological assessment. However, its efficacy might be limited by the size of the targeted lesion. This study aimed to evaluate the feasibility of histopathological assessment of small solid pancreatic lesions using a 22-gauge Franseen needle during EUS-FNB.

METHODS

This retrospective study evaluated data from all patients who underwent EUS-FNB using a Franseen needle for solid pancreatic lesions at the University of Toyama Hospital between June 2018 and April 2020.

RESULTS

The study included 159 patients who had 152 malignant lesions and 7 benign lesions. The malignant lesions included pancreatic cancers (n = 134), neuroendocrine neoplasms (n = 15), metastatic tumors (n = 2), and a solid pseudopapillary neoplasm (n = 1). The diagnostic accuracy of EUS-FNB (combining histology and cytology) was 98.7%. However, the histopathological diagnosis was only confirmed for 64.3% of small lesions (<10 mm), relative to 97.2% for larger lesions. Multivariate analysis also revealed that lesion size of <10 mm predicted a less accurate histopathological diagnosis (odds ratio: 6.97, 95% confidence interval: 1.02-47.67; p = 0.041). Further analyses revealed a failed histological diagnosis in 4 patients with lesions of <5 mm in size and accurate diagnoses in 9 out of 10 patients with lesions of 5-10 mm in size.

CONCLUSIONS

The diagnostic accuracy for small lesions (<10 mm), especially for lesions of <5 mm, based on histological examination alone, was significantly lower than that for others (>10 mm). Furthermore, multivariate analysis revealed that only lesion size was an independent predictor of histopathological diagnosis accuracy.

Tissue acquisition and pancreatic masses: Which needle and which acquisition technique should be used?

Background and study aims  Pancreatic cancer represents the fourth most common cause of cancer-related deaths in Western countries and the need of a low-risk investigation to obtain an accurate histopathological diagnosis has become increasingly pressing. Endoscopic ultrasonography (EUS) with fine-needle aspiration (FNA) is the standard method for obtaining samples from pancreatic masses. In recent years, there has been an increasing need to obtain histological specimens during EUS procedures, rather than cytological ones, to guide oncological treatment options, leading to the so-call "FNB concept." Different needles have been developed for fine-needle biopsy (FNB) in recent years, enabling acquisition of larger specimens on which to perform histological and molecular analyses. The aim of this narrative review was to assess the role of EUS-guided FNA and FNB in patients with pancreatic masses, and to identify which needle and which acquisition technique should be used to improve tissue acquisition.

A prospective, randomized, multicenter clinical trial comparing 25-gauge and 20-gauge biopsy needles for endoscopic ultrasound-guided sampling of solid pancreatic lesions

BACKGROUND

Various core biopsy needles have previously been developed for endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB). However, the properties of needle gauge in the diagnostic outcomes of solid pancreatic lesions remain unknown. This trial compared the procurement rates of histologic cores from solid pancreatic lesions with EUS-FNB using 20- and 25-gauge (G) FNB needles.

METHODS

In a prospective randomized multicenter clinical trial, patients with solid pancreatic lesions underwent EUS-FNB with either a 20-gauge or a 25-gauge FNB needle. The rates of histologic core procurement, overall diagnostic accuracy, and adverse events were compared between the two groups (20-gauge or 25-gauge FNB needle).

RESULTS

In total, 88 patients (48 men, 40 women, mean age 65.7 years) were enrolled. No significant differences were found in the demographic characteristics between the two groups (20-gauge or 25-gauge FNB needle). The procurement rate of histologic cores in the 20-guage FNB needle group (41/45, 91.1%) was significantly higher than that in the 25-guage FNB needle group (32/43, 74.4%, P = 0.037). However, no significant differences were found in the overall diagnostic accuracy between 20-guage FNB needle (40/45, 88.9%) and 25-guage FNB needle (34/43, 79.1%, P = 0.208). No procedure-related adverse events were observed in either group.

CONCLUSIONS

Although both FNB needles provided high overall diagnostic accuracy, the reliability of the 20-guage FNB needle is better than the 25-guage FNB needle when retrieving samples for histological analysis.

Fine needle biopsy is superior to fine needle aspiration in endoscopic ultrasound guided sampling of pancreatic masses: A meta-analysis of randomized controlled trials

BACKGROUND

The comparison between endoscopic ultrasound (EUS) guided fine needle aspiration (FNA) and EUS guided fine needle biopsy (FNB) in sampling pancreatic masses is still controversial.

METHODS

A systematic search was conducted in PubMed and Web of Science to identify all relevant randomized controlled trials (RCTs). Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated for dichotomous outcomes of interest (specimen adequacy, diagnostic accuracy, complications, and technical success), while mean difference (MD) and 95% CI were pooled for continuous variables (number of needle passes required for diagnosis).

RESULTS

Eleven RCTs were identified with a total of 694 EUS-FNA cases and 688 EUS-FNB cases. Compared with EUS-FNA, EUS-FNB had a better specimen adequacy (OR: 1.83, 95% CI: 1.27-2.64), higher diagnostic accuracy (OR: 1.62, 95% CI: 1.17-2.26), and fewer number of needle passes (MD: 0.69, 95% CI: 1.18 to 0.20). No significant difference was found in complications (OR: 1.01, 95% CI: 0.27-3.78) and technical success (OR: 0.13, 95% CI: 0.02-1.07).

CONCLUSION

EUS-FNB is superior to EUS-FNA in sampling pancreatic masses.

Evaluation of 22G fine-needle aspiration (FNA) versus fine-needle biopsy (FNB) for endoscopic ultrasound-guided sampling of pancreatic lesions: a prospective comparison study

Background

To compare the diagnostic yield and safety of 22G endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) and endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) in the diagnosis of pancreatic solid lesions.

Methods

Between April 2014 and September 2015, 36 patients with pancreatic solid lesions were included for endoscopic ultrasound test. Patients were randomly divided into two groups: EUS-FNA (n = 18) and EUS-FNB (n = 18). Each nidus was punctured three times (15 ~ 20 insertions for each puncture) with a 22G needle. The core specimens were analyzed, and the diagnostic yields of FNA and FNB were evaluated.

Results

The procedure success rate was 100% with no complications. Cytological and histological examinations found that the diagnostic yield of FNB and FNA were both 83.3%. To get a definitive diagnosis, FNB needed fewer punctures than FNA (1.11 vs. 1.83; P  <  0.05).

Conclusions

22G EUS-FNB is a safe and effective way to diagnose pancreatic solid lesions. FNB required a lower number of needle passes to achieve a diagnosis compared with FNA.

BioXmark for high-precision radiotherapy in an orthotopic pancreatic tumor mouse model : Experiences with a liquid fiducial marker

BACKGROUND AND PURPOSE

High-precision radiotherapy (RT) requires precise positioning, particularly with high single doses. Fiducial markers in combination with onboard imaging are excellent tools to support this. The purpose of this study is to establish a pancreatic cancer mouse model for high-precision image-guided RT (IGRT) using the liquid fiducial marker BioXmark (Nanovi, Kongens Lyngby, Denmark).

METHODS

In an animal-based cancer model, different volumes of BioXmark (10-50 µl), application forms, and imaging modalities-cone-beam computer tomography (CBCT) incorporated in either the Small Animal Radiation Research Platform (SARRP) or the small-animal micro-CT Scanner (SkyScan; Bruker, Brussels, Belgium)-as well as subsequent RT with the SARRP system were analyzed to derive recommendations for BioXmark.

RESULTS

Even small volumes (10 µl) of BioXmark could be detected by CBCT (SARRP and Skyscan). Larger volumes (50 µl) led to hardening artefacts. The position of BioXmark was monitored at least weekly by CBCT and was stable over 4 months. BioXmark was shown to be well tolerated; no changes in physical condition or toxic side effects were observed in comparison to control mice. BioXmark enabled an exact fusion with the original treatment plan with less hardening artefacts, and minimized the application of contrast agent for fractionated RT.

CONCLUSION

An orthotopic pancreatic tumor mouse model was established for high-precision IGRT using a fiducial marker. BioXmark was successfully tested and provides the perfect basis for improved imaging in high-precision RT. BioXmark enables a unique application method and optimal targeted precision in fractionated RT. Therefore, preclinical trials evaluating novel fractionation regimens and/or combination treatment with high-end RT can be performed.

Endoscopic Ultrasound Elastography: Current Clinical Use in Pancreas

Elastography is a newer technique for the assessment of tissue elasticity using ultrasound. Cancerous tissue is known to be stiffer (hence, less elastic) than corresponding healthy tissue, and as a result, could be identified in an elasticity-based imaging. Ultrasound elastography has been used in the breast, thyroid, and cervix to differentiate malignant from benign neoplasms and to guide or avoid unnecessary biopsies. In the liver, elastography has enabled a noninvasive and reliable estimate of fibrosis. Endoscopic ultrasound has become a robust diagnostic and therapeutic tool for the management of pancreatic diseases. The addition of elastography to endoscopic ultrasound enabled further characterization of pancreas lesions, and several European and Asian studies have reported encouraging results. The current clinical role of endoscopic ultrasound elastography in the management of pancreas disorders and related literature are reviewed.

Rapid on-site cytopathological examination (ROSE) performed by endosonagraphers and its improvement in the diagnosis of pancreatic solid lesions

PURPOSE

To evaluate the diagnosis improvement of EUS-FNA when using ROSE performed by the endosonographer.

METHODS

A retrospective study was conducted. A total of 48 pancreatic solid masses EUS-FNA were divided into two groups according to the availability of on-site cytology (ROSE) - the first 24 patients (group A-without ROSE) and the latter 24 cases (group B-with ROSE). Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, complications and inadequacy rate of EUS-FNA were determined and compared.

RESULTS

Among the 48 EUS-FNA, the overall performance was: sensitivity 82%; specificity 100%; positive predictive value (PPV) 100%; negative predictive value (NPV) 70% and accuracy 87%. The sensitivity of the Group A was 71%, versus 94% in-group B (p=0.61). Moreover, the negative predictive value was 58% versus 87% (p=0.72). The accuracy rate increased from 79% to 96% (p=0.67) in the ROSE group. The number of punctures was similar between the groups. No major complications were reported.

CONCLUSION

Rapid on-site cytopathological examination, even when performed by the endosonographer, may improve the diagnostic performance in the diagnosis of solid pancreatic lesions, regardless of the slight increase in the number of punctures.

Comparison of 22G reverse-beveled versus standard needle for endoscopic ultrasound-guided sampling of solid pancreatic lesions

OBJECTIVES

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) using standard needles has a high diagnostic value in the evaluation of solid pancreatic masses. Fenestrated needles have been developed to improve the quality of EUS-guided tissue sampling by providing core biopsies (FNB).

METHODS

Patients with solid pancreatic masses of >2 cm were prospectively included in our study and randomized to receive EUS sampling, using either a standard 22G FNA or a 22G Procore® FNB needle. The main study endpoint was the number of needle passes required to obtain a diagnosis in more than 90% of cases.

RESULTS

We included 100 patients (male = 63, female = 37; mean age = 68.4 years) in our study. We found that 88% of the lesions were malignant, with a mean size of 32 mm. A sample adequate for diagnosis was obtained in more than 90% of cases after the second needle pass in the FNB group, versus the third needle pass in the FNA group. Slide cellularity and presence of tissue microfragments were significantly higher in the FNB group. Sensitivity for the diagnosis of malignancy was 88.4% versus 97.8% for the EUS-FNA and EUS-FNB group, respectively, while specificity for both techniques was 100%. No complications were recorded.

CONCLUSIONS

Although the accuracy of both needle types for proving malignancy was similar, a lower number of passes was required with the FNB needles to achieve the same contributive sample rate as with the FNA needles. FNB also improved the histopathological quality of specimens, suggesting an overall superiority of FNB sampling.

Technical advances in endoscopic ultrasound-guided fiducial placement for the treatment of pancreatic cancer

Radiation therapy has an important role in the treatment of locally advanced or metastatic pancreatic cancer and can be used alone or in conjunction with surgery and/or systemic chemotherapy. Because of the challenge of delivering an accurate and optimal radiation dose, image-guided radiation therapy can be used to improve targeting. Fiducial markers can be placed in the tumor and used for localization in patients undergoing image-guided radiation therapy. The safety and feasibility of endoscopic ultrasound (EUS)-guided placement of fiducials has been assessed and reported for the management of pancreatic cancer. We herein review the technique, efficacy, and safety profile of EUS-guided fiducial placement. In addition, we highlight recent advances and technological upgrades in EUS-guided fiducial delivery systems for pancreatic cancer most relevant to practicing gastroenterologists and interventional endoscopists.

A triple approach for diagnostic assessment of endoscopic ultrasound-guided fine needle aspiration in pancreatic solid masses and lymph nodes

BACKGROUND AND AIMS

Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) has been becoming the standard tool for acquiring pancreatic lesion tissue. However, a single cytologic or histologic evaluation is not satisfactory for diagnosis. In this study, we evaluated the diagnostic yield of EUS-FNA for pancreatic solid masses and intra-abdominal lymph nodes using a triple approach.

METHODS

This study included patients undergoing evaluation for a solid pancreatic mass (n = 59) or intra-abdominal lymph nodes (n = 16) using EUS-FNA with a 22- or 25-gauge (G) needle, respectively. The specimens from each pass were analyzed by on-site cytology using Diff-Quick stain, cytology using Papanicolaou stain, and histology with immunohistochemical (IHC) staining.

RESULTS

A total of 75 patients (49 males; mean age; 63.7 years) were included. The median number of needle pass for diagnosis of malignancy was 2.0, and there was no technical failure. The diagnostic accuracies with on-site cytology, cytology using Papanicolaou staining, and histology were 70.7, 80.0, and 80.0 %, respectively. The diagnostic accuracy using a triple approach was significantly greater than cytology using Papanicolaou staining alone (94.7 vs. 80.0 %; p = 0.007). In patients with malignant lesions, cytology identified 12 of 71 (16.9 %) malignant lesions that were not diagnosed by histology using IHC, and histology identified six (8.5 %) malignant lesions that were not diagnosed by cytology.

CONCLUSION

On-site cytopathologic evaluation combined with cytologic and histologic analysis with IHC stain for one-pass specimen is considered to be able to increase the overall accuracy of EUS-FNA in pancreatic solid masses and lymph nodes.

Endoscopic ultrasound in the diagnosis and treatment of pancreatic disease

Endoscopic ultrasound (EUS) is an important part of modern gastrointestinal endoscopy and now has an integral role in the diagnostic evaluation of pancreatic diseases. Furthermore, as EUS technology has advanced, it has increasingly become a therapeutic procedure, and the prospect of multiple applications of interventional EUS for the pancreas is truly on the near horizon. However, this review focuses on the established diagnostic and therapeutic roles of EUS that are used in current clinical practice. In particular, the diagnostic evaluation of acute pancreatitis, chronic pancreatitis, cystic pancreatic lesions and solid masses of the pancreas are discussed. The newer enhanced imaging modalities of elastography and contrast enhancement are evaluated in this context. The main therapeutic aspects of pancreatic EUS are then considered, namely celiac plexus block and celiac plexus neurolysis for pain control in chronic pancreatitis and pancreas cancer, and EUS-guided drainage of pancreatic fluid collections.

Molecular imaging in pancreatic cancer--a roadmap for therapeutic decisions

Pancreatic ductaladeno carcinoma (PDAC) is a deadly cancer characterized by multiple molecular alterations, the presence of an intense stroma, poor perfusion, and resistance to therapy. In addition to standard imaging techniques, experimental imaging strategies, such as those utilizing molecular probes, nanoparticle-based agents, and tagged antibodies are actively being explored experimentally. It is hoped that advances in these technologies will allow for detecting PDAC at an early stage, and could serve to validate experimental therapies, rapidly identify non-responders, and assist in the design of novel therapeutic strategies tailored to the patient's molecular profile.

Differentiation of pancreatic cancer and chronic pancreatitis using computer-aided diagnosis of endoscopic ultrasound (EUS) images: a diagnostic test

Background

Differentiating pancreatic cancer (PC) from normal tissue by computer-aided diagnosis of EUS images were quite useful. The current study was designed to investigate the feasibility of using computer-aided diagnostic (CAD) techniques to extract EUS image parameters for the differential diagnosis of PC and chronic pancreatitis (CP).

Methodology/Principal Findings

This study recruited 262 patients with PC and 126 patients with CP. Typical EUS images were selected from the sample sets. Texture features were extracted from the region of interest using computer-based techniques. Then the distance between class algorithm and sequential forward selection (SFS) algorithm were used for a better combination of features; and, later, a support vector machine (SVM) predictive model was built, trained, and validated. Overall, 105 features of 9 categories were extracted from the EUS images for pattern classification. Of these features, the 16 were selected as a better combination of features. Then, SVM predictive model was built and trained. The total cases were randomly divided into a training set and a testing set. The training set was used to train the SVM, and the testing set was used to evaluate the performance of the SVM. After 200 trials of randomised experiments, the average accuracy, sensitivity, specificity, the positive and negative predictive values of pancreatic cancer were 94.2±0.1749%,96.25±0.4460%, 93.38±0.2076%, 92.21±0.4249% and 96.68±0.1471%, respectively.

Conclusions/Significance

Digital image processing and computer-aided EUS image differentiation technologies are highly accurate and non-invasive. This technology provides a kind of new and valuable diagnostic tool for the clinical determination of PC.

Objective assessment of an algorithmic approach to EUS-guided FNA and interventions

BACKGROUND

Despite an increasing number of procedures being performed, there is no consensus on an optimal approach to EUS-guided FNA (EUS-FNA) or interventions.

OBJECTIVE

Validate an algorithmic approach to EUS-FNA/interventions with the objective of improving technical outcomes and resource use.

DESIGN

Prospective study.

SETTING

Tertiary-care referral center.

PATIENTS

Consecutive patients undergoing EUS-FNA and/or interventions.

INTERVENTION

Phase I was a retrospective analysis of EUS-FNA/interventions performed in 548 patients. The 19-gauge needle was used for interventions, and the 22- or 25-gauge needle was used interchangeably for performing FNAs. At phase I, the technical failure rate was 11.5%. Based on these observations, an algorithm was proposed by which all transduodenal FNAs were performed by using a 25-gauge needle and other FNAs with a 22-gauge needle. All transduodenal interventions were performed with a Flexible 19-gauge needle and others with a standard 19-gauge needle. This algorithm was tested prospectively in phase II on 500 patients.

MAIN OUTCOME MEASUREMENTS

Compare technical failure, diagnostic adequacy, procedural complications, and average needle costs between both phases.

RESULTS

The technical failure rate was significantly less in phase II compared with that of phase I (1.6% vs 11.5%; P < .001) for both FNA (1.8% vs 10.9%; P < .001) and therapeutic interventions (0% vs 16.4%; P = .001). Although there was no difference in diagnostic adequacy (97.1% vs 98.4%; P = .191) or complications (0.4% vs 0.2%; P = 1.0) between phases I and II, the average cost per case was significantly less in phase II ($199.59 vs $188.30; P = .008).

LIMITATIONS

Single-center study.

CONCLUSION

An algorithmic approach to EUS-FNA/interventions yielded better technical outcomes and cost savings without compromising diagnostic adequacy.