Introduction

Early diagnosis of pancreatic cancer relies on detecting subtle, indirect signs of minute tumors. Endoscopic ultrasonography (EUS) is crucial for this purpose. However, EUS image construction is influenced not only by the density and structure of the target areas but also by the characteristics of the surrounding tissue. Directly correlating preoperative EUS images and precisely aligning the pathological images of the area of interest remains challenging, as comparisons often rely on approximate anatomical regions. To overcome this limitation and to gain a deeper understanding of EUS imaging capabilities at the microscopic level, the present study examined unfixed pancreatic resection specimens using EUS immediately after surgery.

Aims & Methods

The present study aimed to investigate the characteristics and limitations of EUS imaging by directly comparing EUS images with the corresponding pathological sections of resected pancreatic specimens. The samples derived from distal pancreatectomies for pancreatic ductal adenocarcinoma without chemotherapy (pT1b or less in the UICC classification, 8th edition) were obtained between January 2023 and November. Specimens from pancreatoduodenectomies were excluded to enable a precise, one-to-one comparison between the pathological specimens and EUS images. The resected specimens were immersed in saline and examined using a convex-type EUS scope (Olympus UCT260/ME-2, Tokyo, Japan). Areas of interest, including the main tumor site and any abnormal findings, were marked with nylon sutures. HE-stained pathological sections from these marked areas were then directly compared with the corresponding EUS images to evaluate the imaging characteristics of various pathological features.

Results

The present study included four male and three female patients with a mean age of 76.3 years. The tumor location included the pancreatic body (n = 5) and the tail (n = 2). According to the 8th edition of the UICC classification, the pathological T stage was Tis, T1a, and T1b in four, two, and one cases, respectively. The pathological findings of 24 samples were compared with the corresponding EUS images. The rate of detection of the specific pathological features using EUS was 0%, 33%, 64%, 47%, and 60% for PanIN lesions, invasive carcinoma, localized pancreatic atrophy (predominantly fatty), localized pancreatic atrophy (predominantly fibrotic), and pancreatic cysts ≤ 2 mm, respectively. Solitary cysts ≤ 2 mm were often identifiable, while multiple, clustered cysts appeared as faint, hypoechoic areas. Localized pancreatic atrophy with predominant fibrosis appeared as a faint, hypoechoic area, and atrophy with predominantly fatty replacement appeared as a high-intensity area within the parenchyma. However, complete fatty replacement obscured the boundary with surrounding fatty tissue, leading to its appearance as loss of the pancreatic parenchyma.

Conclusion

The present findings demonstrated that despite its high diagnostic accuracy for pancreatic diseases, EUS is limited in its ability to visualize tissue microarchitecture. Understanding the specific imaging features of localized pancreatic atrophy and small pancreatic cysts on EUS is crucial for improving the accuracy of early diagnoses of pancreatic cancer. The insights gained from this one-to-one comparison of the EUS findings and pathological specimens can contribute to enhancing the precision of the diagnosis and facilitate the earlier detection of pancreatic cancer.

Introduction

Endoscopic retrograde cholangiopancreatography (ERCP) with stent placement is the current standard for drainage of distal malignant biliary obstruction (MBO), but carries a significant risk of post-procedural pancreatitis.[1] EUS-guided choledochoduodenostomy (EUS-CDS) is increasingly used as a promising alternative, but comparative studies are still scarce.[2,3] While previous studies have mainly focused on stent patency, the current study aims to evaluate whether EUS-CDS is superior to ERCP in achieving a textbook outcome for the patients, indicating an optimal post-procedural course.

Aims & Methods

This single-center study included patients with distal MBO who underwent technically successful (1) EUS-CDS with a lumen apposing metal stent (LAMS) plus additional coaxial stent or (2) ERCP with fully covered self-expandable metal stent (FCSEMS) as part of the prospective SCORPION studies and SPHINX trial, respectively.[1,4] The primary endpoint was textbook outcome, defined as the absence of procedure- or stent-related adverse events (AEs), reinterventions, or hospital readmissions within 30 days of the procedure. Secondary endpoints included individual components of the primary outcome, mortality, time to initiation of treatment (e.g., systemic therapy or surgery), and textbook outcome at 90 days.

Results

A total of 144 patients were enrolled for EUS-CDS (n=49) or ERCP (n=95). Primary etiologies included pancreatic cancer (n=117, 81%) and distal cholangiocarcinoma (n=14, 10%). Coaxial stents used in the EUS-CDS group were FCSEMS (n=20) or double pigtail plastic stents (n=29). Textbook outcome was achieved in 44 patients (90%) in the EUS-CDS group and in 67 patients (71%) in the ERCP group at 30 days (RR 1.27, 95% CI 1.08-1.50). EUS-CDS led to fewer procedure- or stent-related AEs (RR 0.35, 95% CI 0.14-0.84) compared with ERCP, particularly post-procedure pancreatitis (0% vs. 23%). Other AEs, including perforation (2% vs. 0%), bleeding (0% vs. 0%), stent dysfunction with or without cholangitis (4% vs. 6%), and cholecystitis (4% vs. 3%) were similar between groups. Hospital readmission rate was lower in the EUS-CDS group (6% vs. 30%, RR 0.21, 95% CI 0.07-0.65), as was the length of hospital stay (mean 0.3 days [SD 1.3] vs. 1.8 days [SD 4.0], P=0.01). In-hospital mortality (8% vs. 5%), need for reinterventions (8% vs. 6%), and time to treatment initiation, either surgery or chemotherapy, did not differ (median 33 days [IQR 23-42] vs. 30 days [IQR 18-41]). At 90 days, textbook outcome was more often present in the EUS-CDS group when compared to ERCP however the difference was no longer significant (78% vs. 69%, RR 1.22, 95% CI 1.02-1.44).

Conclusion

EUS-CDS with LAMS and additional coaxial stent was superior to ERCP with FCSEMS in achieving textbook outcome at 30 days post-procedure. EUS-CDS resulted in less procedure- or stent-related AEs, particularly post-procedure pancreatitis, and consequently in fewer hospital readmissions and shorter hospital stay. Therefore, when expertise is available, EUS-CDS with coaxial stent placement could be considered as primary biliary drainage technique in patients with distal MBO.

References

1. Onnekink, A. M., Gorris, M., Bekkali, N. L., et al (2024). Endoscopic sphincterotomy to prevent post-ERCP pancreatitis after self-expandable metal stent placement for distal malignant biliary obstruction (SPHINX): a multicentre, randomised controlled trial. Gut, gutjnl-332695. https://doi.org/10.1136/gutjnl-2024-332695
2. Teoh, A. Y. B., Napoleon, B., Kunda, R et al (2023). EUS-Guided choledocho-duodenostomy using lumen apposing stent versus ERCP with covered metallic stents in patients with unresectable malignant distal biliary obstruction: a multicenter randomized controlled trial (DRA-MBO trial). Gastroenterology, 165(2), 473-482.e2. https://doi.org/10.1053/j.gastro.2023.04.016
3. Chen, Y., Sahai, A., Donatelli, G. et al (2023). Endoscopic Ultrasound-Guided Biliary Drainage of First Intent With a Lumen-Apposing Metal Stent vs Endoscopic Retrograde Cholangiopancreatography in Malignant Distal Biliary Obstruction: A Multicenter Randomized Controlled Study (ELEMENT Trial). Gastroenterology, 165(5), 1249-1261.e5. https://doi.org/10.1053/j.gastro.2023.07.024
4. Fritzsche, J. A., Fockens, P., Besselink, M. G. et al (2024). Optimizing EUS-guided choledochoduodenostomy with lumen-apposing metal stents for primary drainage of malignant distal biliary obstruction (SCORPION-IIp): a prospective pilot study. Gastrointestinal Endoscopy. https://doi.org/10.1016/j.gie.2024.10.012

Disclosure

Paul Fockens acted as a consultant for Cook Endoscopy and Olympus, outside the submitted work.
Roy L.J. van Wanrooij acted as a consultant for Boston Scientific. Jeanin E. van Hooft has received research support from Cook Medical and acted as lecturer for Cook Medical, Boston Scientific and Falk, and as consultant for Olympus. Rogier P. Voermans received a research grant and acted as consultant for Boston Scientific. All outside the submitted work. All other authors declare that they have no competing financial interests or personal relationships that could have appeared to influence the work reported in this abstract.

Introduction

Aims & Methods

Results

Conclusion

References