Immediate Necrosectomy vs. Step-up Approach for Walled-off Necrosis

Walled-off necrosis (WON) is a pancreatic fluid collection, which contains necrotic tissue after four weeks of the onset of acute pancreatitis. Interventions are required to manage patients with infected WON, for which endoscopic ultrasonography (EUS)-guided drainage has become a first-line treatment modality. For patients who are refractory to EUS-guided drainage, the step-up treatment including endoscopic necrosectomy (EN) and/or additional drainage is considered to subside the infection. Recent evidence suggests that EN immediately after EUS-guided drainage may shorten treatment duration without increasing adverse events. In this randomized trial, the investigators will compare treatment duration between EN immediately after EUS-guided drainage versus the step-up approach in patients with symptomatic WON.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

* Patients with WON defined according to the revised Atlanta classification
* The longest diameter of WON is 4 cm or larger
* Patients with at least one out of the following conditions; signs of infection, gastrointestinal symptoms, abdominal symptoms, obstructive jaundice
* Patients who need drainage for WON
* Age of 18 years or older
* Patients or their representatives provide informed consent
* Patients who visit or are hospitalized at the participating institutions

Exclusion Criteria:

* WON inaccessible by EUS-guided approach
* AXIOS stent has already been placed into the WON prior to the enrollment
* Severe coagulopathy; Platelet count \< 50,000/mm3 or prothrombin time international normalized ratio (PT-INR) \>1.5
* Patients on antithrombotic agents which cannot be managed according to the "guideline for gastroenterological endoscopy in patients undergoing antithrombotic treatment (Dig Endosc. 2014 Jan;26(1):1-14.)"
* Patients who cannot tolerate endoscopic procedures
* Pregnant women
* Patients considered inappropriate for inclusion by investigators

• BACKGROUNDBanks PA, Bollen TL, Dervenis C, Gooszen HG, Johnson CD, Sarr MG, Tsiotos GG, Vege SS; Acute Pancreatitis Classification Working Group. Classification of acute pancreatitis--2012: revision of the Atlanta classification and definitions by international consensus. Gut. 2013 Jan;62(1):102-11. doi: 10.1136/gutjnl-2012-302779. Epub 2012 Oct 25. PMID 23100216
• DERIVEDSaito T, Fujisawa T, Ogura T, Kuwatani M, Ohyama H, Takenaka M, Doi S, Iwata K, Hashimoto S, Kamada H, Iwashita T, Shiomi H, Masuda A, Matsubara S, Hayashi N, Maruta A, Kogure H, Inoue T, Yamada R, Shiratori T, Hamada T, Ueno S, Okuda A, Takahashi S, Sugiura R, Kawakubo K, Takahashi K, Kan M, Omoto S, Yamazaki T, Katsukura N, Okuno M, Hinokuchi M, Namima D, Uemura S, Nakano R, Sakai A, Suda K, Yoshida K, Saito K, Kitano R, Nose K, Nakaji S, Mukai T, Nakahara K, Chinen K, Isayama H, Yasuda I, Nakai Y; WONDERFUL study group in Japan and collaborators. Immediate or On-Demand Endoscopic Necrosectomy for Necrotizing Pancreatitis: A Randomized Controlled Trial (WONDER-01). Gastroenterology. 2026 Jul;171(1):140-153. doi: 10.1053/j.gastro.2026.01.034. Epub 2026 Feb 18. PMID 41720198
• DERIVEDSato T, Saito T, Takenaka M, Iwashita T, Shiomi H, Fujisawa T, Hayashi N, Iwata K, Maruta A, Mukai T, Masuda A, Matsubara S, Hamada T, Inoue T, Ohyama H, Kuwatani M, Kamada H, Hashimoto S, Shiratori T, Yamada R, Kogure H, Ogura T, Nakahara K, Doi S, Chinen K, Isayama H, Yasuda I, Nakai Y; WONDERFUL study group in Japan, collaborators. WONDER-01: immediate necrosectomy vs. drainage-oriented step-up approach after endoscopic ultrasound-guided drainage of walled-off necrosis-study protocol for a multicentre randomised controlled trial. Trials. 2023 May 24;24(1):352. doi: 10.1186/s13063-023-07377-y. PMID 37226252