To the Editor:
Park et al
1
reported no significant differences in the 6-month stent patency rates and mortality between partially covered and uncovered double bare self-expandable metal stents (PCDBSs vs UCDBSs) for unresectable distal malignant biliary obstruction. This randomized controlled multicenter trial is of great significance for clinical practice, yet we would like to share our reservations for further research.First, as shown in the baseline characteristics section, the length of the stricture was longer in PCDBSs than in UCDBSs (2.8 ± 1.3 vs 2.4 ± 1.2, P = .010). The length or the degree of stricture might be correlated with disease severity and stent patency,
2
and longer biliary stricture was an independent risk factor for worse survival after metal stent insertion,3
which is also in accord with the fact that the rate of tumor overgrowth was higher in the PCDBS group than in the UCDBS group (5.5% vs 0.8%). Therefore, we hypothesize that the PCDBS group had selection bias, which would weaken the effect of PCDBSs on stent patency and overall survival, and a propensity-matching analysis may be required.Second, we would like to know whether there was a significant difference in the total incidence of single adverse events between the 2 groups, regardless of the 2-week time limit, so as to better verify the overall impact of whether or not the novel metal stent is covered on the risk of adverse events.
4
Third, the authors did not disclose the details of revision for stent dysfunction, which might have had some influence on stent patency and overall survival. For example, radiofrequency ablation can be performed by both endoscopic and percutaneous routes. As a novel adjunctive procedure and a promising therapeutic option in patients with malignant biliary obstruction, radiofrequency ablation can achieve local tumor control, resulting in improved biliary stent patency and a potential survival benefit.
5
Disclosure
Both authors disclosed no financial relationships.
References
- Covered versus uncovered double bare self-expandable metal stent for palliation of unresectable extrahepatic malignant biliary obstruction: a randomized controlled multicenter trial.Gastrointest Endosc. 2023; 97: 132-142.e2
- Features of malignant biliary obstruction affecting the patency of metallic stents: a multicenter study.Gastrointest Endosc. 2002; 55: 359-365
- Percutaneous transpapillary biliary stent placement for distal malignant biliary obstruction: outcomes and survival analysis.Turk J Gastroenterol. 2019; 30: 714-721
- ERCP-related adverse events: European Society of Gastrointestinal Endoscopy (ESGE) guideline.Endoscopy. 2020; 52: 127-149
- Updated evidence on the clinical impact of endoscopic radiofrequency ablation in the treatment of malignant biliary obstruction.Dig Endosc. 2022; 34: 345-358
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