Can delayed endoscopic drainage of pancreatic walled-off collection be replaced by early drainage?

Acute pancreatitis (AP) is a common condition encountered by both general practitioners and gastroenterologists. With the development of necrotizing pancreatitis, walled-off necrosis (WON) may occur. It is advocated that endoscopic drainage should be performed 4 weeks after the onset of AP.1Baron T.H. DiMaio C.J. Wang A.Y. et al.American Gastroenterological Association clinical practice update: management of pancreatic necrosis.Gastroenterology. 2020; 158: 67-75Abstract Full Text Full Text PDF PubMed Scopus (284) Google Scholar Therefore, we read with great interest the systemic review and meta-analysis by Ramai et al.2Ramai D. Enofe I. Deliwala S.S. et al.Early (<4 weeks) versus standard (≥4weeks) endoscopic drainage of pancreatic walled-off fluid collections: a systematic review and meta-analysis.Gastrointest Endosc. 2023; 97: 415-421Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar This meta-analysis may be included in future guidelines for acute necrotizing pancreatitis. However, there are some flaws in the meta-analysis. First, we found that the study by Chantarojanasiri et al was not included in the meta-analysis, as illustrated in the forest plot of clinical success.2Ramai D. Enofe I. Deliwala S.S. et al.Early (<4 weeks) versus standard (≥4weeks) endoscopic drainage of pancreatic walled-off fluid collections: a systematic review and meta-analysis.Gastrointest Endosc. 2023; 97: 415-421Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar,3Chantarojanasiri T. Yamamoto N. Nakai Y. et al.Comparison of early and delayed EUS-guided drainage of pancreatic fluid collection.Endosc Int Open. 2018; 6: E1398-E1405Crossref PubMed Google Scholar We used the same data to perform meta-analyses. We found that the forest plot of clinical success was different from that of the study by Ramai et al2Ramai D. Enofe I. Deliwala S.S. et al.Early (<4 weeks) versus standard (≥4weeks) endoscopic drainage of pancreatic walled-off fluid collections: a systematic review and meta-analysis.Gastrointest Endosc. 2023; 97: 415-421Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar as illustrated in Figure 1. We are very happy that the conclusion is not changed by the omission of the study by Chantarojanasiri et al. Second, the systemic review did not analyze publication bias. We used a funnel plot to assess publication bias.4Higgins JPT, Thomas J, Chandler J, et al (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.3 (updated February 2022). Cochrane, 2022. Available from www.training.cochrane.org/handbook. Accessed April 3, 2023.Google Scholar The funnel plot showed obvious asymmetry as illustrated in Figure 2. Moreover, we identified another study comparing early with delayed endoscopic drainage for pancreatic walled-off fluid collections.5Bomman S. Sanders D. Coy D. et al.Safety and clinical outcomes of early dual modality drainage (<28 days) compared to later drainage of pancreatic necrotic fluid collections: a propensity score-matched study.Surg Endosc. 2023; 37: 902-911Crossref PubMed Scopus (2) Google Scholar Thus, publication bias is evident in the systemic review. In conclusion, whether early endoscopic drainage for pancreatic walled-off fluid collections should be advocated is not conclusive. More clinical evidence is still needed. Furthermore, early or delayed drainage should be based on clinical settings. The speed of WON size development and complicated infections may be the most important determinants for early or delayed intervention. Retrospective or cohort studies have their innate limitations and biases. Randomized controlled trials in the future may come to definite conclusions. Both authors disclosed no financial relationships.