EUS and related technologies for the diagnosis and treatment of pancreatic disease: research gaps and opportunities-Summary of a National Institute of Diabetes and Digestive and Kidney Diseases workshop

Endoscopic Ultrasound-Guided Fine-Needle Biopsy Versus Aspiration for Tissue Sampling Adequacy for Molecular Testing in Pancreatic Ductal Adenocarcinoma

BACKGROUND AND AIMS

There is limited literature on sample adequacy for molecular testing in pancreatic ductal adenocarcinoma obtained via endoscopic ultrasound (EUS) fine-needle aspiration (FNA) versus EUS fine-needle biopsy (FNB). We aimed to compare these two modalities regarding sample adequacy for molecular and genomic sequencing.

METHODS

We reviewed all patients with pancreatic ductal adenocarcinoma who underwent EUS at Saint Luke's Hospital from 2018 to 2021. The patients were categorized based on the method of EUS tissue acquisition, specifically FNA or FNB. A comprehensive evaluation was conducted for all cases by cytotechnologists.

RESULTS

Out of 132 patients who underwent EUS-guided biopsies, 76 opted for FNA, 48 opted for FNB, and 8 opted for a combination of both. The average number of passes required for FNB and FNA was 2.58 ± 1.06 and 2.49 ± 1.07, respectively (p = 0.704), indicating no significant difference. Interestingly, 71.4% (35) of FNB-obtained samples were deemed adequate for molecular testing, surpassing the 32.1% (26) adequacy observed with FNA (p < 0.001). Additionally, 46.4% (26) of FNB-obtained samples were considered adequate for genomic testing, a notable improvement over the 23.8% (20) adequacy observed with FNA (p = 0.005).

CONCLUSION

Although the number of passes required for cytologic diagnosis did not differ significantly between EUS-FNB and EUS-FNA, the former demonstrated superiority in obtaining samples adequate for molecular testing. Tumor surface area and cellularity were crucial parameters in determining sample adequacy for molecular testing, irrespective of the chosen tissue acquisition modality.

Endoscopic Ultrasound Guided Shear Wave Elastography Is Safe With High Feasibility and Reproducibility When Used in the Pancreas: Findings From a Prospective Cohort

OBJECTIVES

The aim of this study was to assess the safety, feasibility, and reproducibility of endoscopic ultrasound shear wave elastography (EUS-SWE) in the pancreas.

METHODS

This is a prospective registry of consecutive patients undergoing clinically indicated EUS. Ten readings of SWE velocities (Vs [distance/time, m/s]) were obtained in the head (HOP), body, and tail of pancreas to quantify tissue stiffness. Each Vs score was accompanied by a reliability measurement VsN (%) with VsN >50% considered reliable. Safety was evaluated by perioperative complications rate. Feasibility was determined by technical success of obtaining measurements. Reproducibility was evaluated using intraclass correlation coefficient analysis.

RESULTS

Total of 3320 EUS-SWE measurements were performed on 117 patients without perioperative complications. Measurement success rate was 100% across all locations. Reliable measurements were more common in the HOP (953/1120 [85.1%]) followed by body (853/1130 [75.5%]) and tail of pancreas (687/1070 [64.2%]) (P < 0.001). The analysis showed good reproducibility in all locations (intraclass correlation coefficient range, 0.80-0.89).

CONCLUSIONS

Endoscopic ultrasound-SWE is safe, has 100% technical success rate, and is highly reproducible when used in the pancreas. Our study suggests that SWE measurements in the HOP offer the highest reliability, likely because of large study area and less respiratory artifact.

Natural history, clinical characteristics, outcomes, and long-term follow-up of pain-free chronic pancreatitis

Background

Chronic pancreatitis (CP) is characterized by chronic abdominal pain and functional insufficiency. However, a small subset of patients with prior acute pancreatitis (AP) and/or underlying risk factors for developing CP may be pain-free at diagnosis and may have a different clinical course. We aimed to compare the clinical characteristics, outcomes, and healthcare utilization between CP patients with and without pain.

Methods

Reviewed patients with established CP were followed in our Pancreas Center between January 2016 and April 2021. Patients without risk factors for developing CP and/or without AP prior to their diagnosis and only with incidental radiologic features of CP were excluded, so as to minimize confounding factors of pancreatopathy unrelated to CP. Patients were divided into painful and pain-free groups to analyze differences in demographics, outcomes, and healthcare utilization.

Results

Of 368 CP patients, 49 (13.3%) were pain-free at diagnosis and had remained so for >9 years. There were no significant differences in body mass index, race, sex, or co-morbidities between the two groups. Pain-free patients were older at diagnosis (53.9 vs 45.7, P = 0.004) and had less recurrent AP (RAP) (43.8% vs 72.5%, P < 0.001) and less exocrine pancreatic insufficiency (EPI) (34.7% vs 65.7%, P < 0.001). Pain-free patients had less disability (2.2% vs 22.0%, P = 0.003), mental illness (20.4% vs 61.0%, P < 0.001), surgery (0.0% vs 15.0%, P = 0.059), and therapeutic interventions (0.0% vs 16.4%, P = 0.005) for pain.

Conclusions

We described a unique subset of patients with underlying risk factors for CP and/or prior AP who were pain-free at diagnosis. They were older at diagnosis, had less EPI and RAP, and overall favorable outcomes with minimal resource utilization.

Robust Descriptor of Pancreatic Tissue for Automatic Detection of Pancreatic Cancer in Endoscopic Ultrasonography

Pancreatic cancer (PC) has a reported mortality of 98% and a 5-y survival rate of 6.7%. Experienced gastroenterologists detect 80% of those with early-stage PC by endoscopic ultrasonography (EUS). Here we propose an automatic second reader strategy to detect PC in an entire EUS procedure, rather than focusing on pre-selected frames, as the state-of-the-art methods do. The method unmasks echo tumoral patterns in frames with a high probability of tumor. First, speeded up robust features define a set of interest points with correlated heterogeneities among different filtering scales. Afterward, intensity gradients of each interest point are summarized by 64 features at certain locations and scales. A frame feature vector is built by concatenating statistics of each feature of the 15 groups of scales. Then, binary classification is performed by Support Vector Machine and Adaboost models. Evaluation was performed using a data set comprising 55 participants, 18 of PC class (16,585 frames) and 37 subjects of non-PC class (49,664 frames), randomly splitting 10 times. The proposed method reached an accuracy of 92.1%, sensitivity of 96.3% and specificity of 87.8.3%. The observed results are also stable in noisy experiments while deep learning approaches fail to maintain similar performance.

Cumulative sum learning curves guiding multicenter multidisciplinary quality improvement of EUS-guided tissue acquisition of solid pancreatic lesions

Background and study aims  In this study, we evaluated the performance of community hospitals involved in the Dutch quality in endosonography team regarding yield of endoscopic ultrasound (EUS)-guided tissue acquisition (TA) of solid pancreatic lesions using cumulative sum (CUSUM) learning curves. The aims were to assess trends in quality over time and explore potential benefits of CUSUM as a feedback-tool. Patients and methods  All consecutive EUS-guided TA procedures for solid pancreatic lesions were registered in five community hospitals between 2015 and  2018. CUSUM learning curves were plotted for overall performance and for performance per center. The American Society of Gastrointestinal Endoscopy-defined key performance indicators, rate of adequate sample (RAS), and diagnostic yield of malignancy (DYM) were used for this purpose. Feedback regarding performance was provided on multiple occasions at regional interest group meetings during the study period. Results  A total of 431 EUS-guided TA procedures in 403 patients were included in this study. The overall and per center CUSUM curves for RAS improved over time. CUSUM curves for DYM revealed gradual improvement, reaching the predefined performance target (70 %) overall, and in three of five contributing centers in 2018. Analysis of a sudden downslope development in the CUSUM curve of DYM in one center revealed temporary absence of a senior cytopathologist to have had a temporary negative impact on performance. Conclusions  CUSUM-derived learning curves allow for assessment of best practices by comparison among peers in a multidisciplinary multicenter quality improvement initiative and proved to be a valuable and easy-to-interpret means to evaluate EUS performance over time.

Role of Ancillary Testing on Endoscopic US-Guided Fine Needle Aspiration Samples from Cystic Pancreatic Neoplasms

Pancreatic cysts are increasingly detected on imaging studies. Accurate determination of the cyst type is important to provide appropriate care for the patients. It is also very clear that not one single modality can provide adequate diagnostic information. A multidisciplinary approach is the key to the diagnosis of pancreatic cysts. In this setting, the role of ancillary testing, which includes biochemical testing (carcinoembryonic antigen and amylase levels in the cyst), molecular testing (e.g., KRAS, GNAS, VHL, and CTNB1), and/or immunohistochemical tests are very important to obtain an accurate diagnosis. This review will discuss helpful ancillary tests in common pancreatic cyst neoplasms and how to approach the diagnosis of pancreatic cysts.

Collaboration of community hospital endosonographers improves diagnostic yield of endoscopic ultrasonography guided tissue acquisition of solid pancreatic lesions

Background and study aims  Endoscopic ultrasound (EUS)-guided tissue acquisition (TA) is the method of choice for establishing a pathological diagnosis of solid pancreatic lesions. Data on quality and yield of EUS-guided TA performed in community hospitals are lacking. A study was performed to determine and improve the diagnostic yield of EUS-guided TA in a group of community hospitals. Methods  Following analysis of the last 20 EUS-guided TA procedures of solid pancreatic lesions performed in each of four community hospitals, a collaborative EUS interest group was formed and a prospective registry was started. During meetings of the interest group, feedback on results per center were provided and strategies for improvement were discussed. Results  In the BEFORE team formation cohort, 80 procedures were performed in 66 patients. In the AFTER team formation cohort, 133 procedures were performed in 125 patients. After team formation, the rate of adequate sample increased from 80 % (95 %CI [0.7 - 0.9]) to 95 % (95 %CI [0.9 - 1.0]) , diagnostic yield of malignancy improved from 28 % (95 %CI [0.2 - 0.4]) to 64 % (95 % CI [0.6 - 0.7]), and sensitivity of malignancy improved from 63 % (95 %CI [0.4 - 0.8]) to 84 % (95 %CI [0.8 - 0.9]). Multivariate regression analysis revealed team formation to be the only variable significantly associated with an increased rate of adequate sample. Conclusions  Formation of a regional EUS interest group with regular feedback on results per center, and discussions on methods and techniques used, significantly improved the outcome of EUS-guided TA procedures in patients with solid pancreatic lesions in community hospitals.

Comparison of endoscopic ultrasound tissue acquisition methods for genomic analysis of pancreatic cancer

BACKGROUND AND AIM

Tumor genotyping may allow for improved prognostication and targeted therapy for pancreatic ductal adenocarcinoma (PDAC). We aimed to compare endoscopic ultrasonography (EUS) with fine needle aspiration (FNA) to fine needle biopsy (FNB) for obtaining sufficient tissue for genomic analysis and theranostic potential.

METHODS

A retrospective cohort study of patients that underwent EUS-FNA or EUS-FNB with either positive or suspicious cytology for PDAC between March 2016 and December 2017. Demographic, procedural, and cytology data were recorded. Genetic alterations were recorded, and Kaplan-Meier survival curves were calculated.

RESULTS

The study included 167 patients: 145 patients had FNA and 22 patients underwent FNB. Overall, 117 samples (70.1%) were sufficient for targeted next-generation sequencing. FNB resulted in a higher proportion of patients with sufficient samples compared with FNA (90.9% vs 66.9%; P = 0.02). In multivariable modeling, only FNB (odds ratio 4.95, 95% confidence interval 1.11-22.05, P = 0.04) was associated with sufficient sampling for genomic testing. FNB was more likely to obtain sufficient tissue from tumors ≤ 3 cm (100% vs 68.4%, P = 0.017) and tumors located in the head/neck of the pancreas (100% vs 63.1%, P = 0.03) compared with FNA. The most commonly identified alterations were in KRAS (88%), TP53 (68%), and SMAD4 (16%).

CONCLUSIONS

Endoscopic ultrasonography can reliably obtain sufficient tissue from PDAC for targeted genomic sequencing for prognostication and theranostics. FNB should be considered when tumor genotyping is requested, especially for tumors ≤ 3 cm or tumors located in the head/neck of the pancreas.

Future Perspectives on Endoscopic Ultrasonography-Guided Therapy for Pancreatic Neoplasm

Endoscopic ultrasonography (EUS)-guided therapy with ethanol injection or catheter-based radiofrequency ablation for pancreatic neoplasm has been conducted as a potential alternate treatment modality for patients who are not eligible for surgery. On the basis of the limited number of studies available, EUS-guided ablation therapy with the aforementioned methods for small pancreatic neoplasms has demonstrated promising technical feasibility and safety profiles. To be considered as a legitimate alternative option to surgery, however, EUS-guided ablation therapy must provide a long-term efficacy profile along with the consensus among experts regarding its treatment parameter. This review focuses on the clinical issues and future perspectives of EUS-guided therapy for pancreatic neoplasm.