Introduction

Pancreatic cancer remains a devastating disease with a poor prognosis, and liquid biopsy utilizing minimally invasive biofluids such as blood and duodenal juice has emerged as a promising approach for early detection. Our group has previously accumulated data on plasma- and duodenal fluid-based liquid biopsy, demonstrating potential clinical utility but also highlighting limitations in diagnostic sensitivity. This study aims to establish a robust cancer diagnostic and risk assessment method using plasma, duodenal juice, and pancreatic juice, while also charactering molecular abnormalities in resected tumors and surrounding tissues. To develop a novel clinical diagnostic framework, we comprehensively evaluated to cancer-associated genetic mutations in biofluids and compared these finding with tissue samples obtained via biopsy or surgical resection.

Aims & Methods

This multi-institutional study, initiated in 2021, focuses on developing a liquid biopsy platform for pancreatic cancer detection. Samples were collected as follows: plasma (n=224), duodenal juice (n=102), and pancreatic juice (n=85). Plasma was collected in 10 mL PAXgene Blood ccfDNA tubes (BD); cell-free DNA (cfDNA) was purified and concentrated to a 30 µL eluate. Duodenal fluid was collected through the endoscopic channel, and pancreatic juice was aspirated directly from the pancreatic duct using a catheter during ERP examination. Both fluid were each mixed with a preservation solution validated in a previous study. Digital PCR (dPCR) was performed to screen for KRAS G12/G13 and A59/Q61 mutations, followed by panel-based sequencing. For this study, we designed a Duplex UMI-based pancreatic cancer gene panel targeting 16 genes, including KRAS, TP53, CDKN2A, and SMAD4, to enable high sensitive detection of tumor-specific mutations.

Results

DPCR screening detected KRAS mutations in 75% of pancreatic juice samples and 50% of duodenal juice samples. Validation of the Duplex UMI-based target sequencing panel in a subset of samples (n=16) demonstrated that a minimum input of 20 ng of liquid-derived, non-genomic DNA was necessary to achieve concordance with mutations identified in matched tissue samples. Inputs below this threshold resulted in significantly reduced coverage and uniformity. Notably, duodenal and pancreatic juice exhibited superior sensitivity, reliably detecting tissue-confirmed mutations down to a minimum variant allele frequency (VAF) of 0.1%. Pancreatic juice not only captured a diverse spectrum of genetic alterations across multiple lesions but also identified mutations absent in corresponding tissue samples, suggesting its potential for detecting subclinical molecular changes. These findings underscore the complementary roles of different biofluids in capturing tumor heterogeneity.

Conclusion

Pancreatic juice-derived DNA shows exceptional promise for the accurate prediction of tumorous lesions, offering a powerful tool to prompt further diagnostic evaluation even in the absence of histological evidence. This approach could substantially enhance early detection and risk stratification in pancreatic cancer. Our ongoing study involves comprehensive analysis of all collected samples using the designed 16-gene panel. These efforts aim to establish liquid biopsy as a central component of pancreatic cancer diagnostics, supporting personalized treatment strategy and improving patient outcomes.

Disclosure

Y.O., K.T. and Y.M. receive funding form Hitachi High-Tech Corporation

Introduction

EUS-guided Gastroenterostomy (EUS-GE) represents a recent breakthrough in therapeutic endosonography, with most existing data derived from retrospective studies focused on short-term technical outcomes. Limited information is available on long-term outcomes, the need for reinterventions and modifications of Lumen Apposing Metal Stents (LAMS) over time.

Aims & Methods

All consecutive EUS-GE performed in a single institution with the Wireless Simplified Technique (WEST) between 2020 and 2024 were enrolled in a prospective registry (PROTECT, ClinicalTrials.gov NCT04813055), with efficacy and safety outcomes assessed every 60 days. The primary outcomes were symptom recurrence after initial clinical success (rate, proportion) and dysfunction-free survival (DyFS) estimated using Kaplan Meier curves. Endoscopic LAMS reassessments were used to calculate the time to first modification of the stent and surrounding tissues, whilst Radiologic imaging was used to estimate the change in stent calibre (linear regression).

Results

164 EUS-GEs (median age 66 [60-74], male 52.4%, malignant indication 99.4% [pancreatic cancer 73.2%, metastatic 58.3%]) were included. A 20 mm LAMS was used in 98.8%, dilated up to 18 mm in 98.8% of cases. Technical and Clinical success rates were 98.8% and 96.3%, respectively. Adverse events (AEs) were registered in 15.2% (procedure-related 6.1%, severe/fatal 3.7%).
Over a median follow-up of 112 [40-190] days, symptom recurrence occurred in 9.1%, but was related to stent dysfunctions in 10/154 (6.5%) cases. Stent dysfunctions happened after a median of 231 [67-321] days from the procedure, all of which (100%) were successfully managed endoscopically. Estimated DyFS at 6 and 12 months was 97.5% and 82.6%, respectively.
Among 38 patients undergoing endoscopic LAMS re-evaluation for different reasons, tissue reactions on the gastric or jejunal side were observed in 34.2% after a median of 190 [33-351] days, and LAMS ingrowth was seen in 13.2% after a median of 421 [250-560] days. A total of 132 CT scans from 75 patients were analysed, with regression analysis revealing a reduction in LAMS diameter of ≈ 0.25 mm + 0.03 every 2 months (F-test p<.0001).

Conclusion

In the natural history of EUS-GE, subclinical LAMS changes and tissue reactions can be frequently detected during follow-up along with a progressive narrowing of LAMS diameter. However, most of these modifications are asymptomatic, with a 6.5% rate of endoscopic reinterventions, all performed successfully. Analysis of these curves may be helpful to plan scheduled reinterventions, especially in cases with benign indication or in long-term survivors.