Advancements in stent strategies for malignant distal biliary obstruction: defining the clinical role of multi-hole self-expandable metal stents

Sung Yong Han

doi:10.5946/ce.2025.210

Articles

Page Path: HOME > Clin Endosc > Volume 58(5); 2025 > Article

Editorial Advancements in stent strategies for malignant distal biliary obstruction: defining the clinical role of multi-hole self-expandable metal stents: Sung Yong Han; Clinical Endoscopy 2025;58(5):698-700.
DOI: https://doi.org/10.5946/ce.2025.210
Published online: September 1, 2025

Department of Internal Medicine, Pusan National University School of Medicine and Biomedical Research Institute, Pusan National University Hospital, Busan, Korea

Corresponding Author: Sung Yong Han Department of Internal Medicine, Pusan National University School of Medicine and Biomedical Research Institute, Pusan National University Hospital, 179 Gudeok-ro, Seo-gu, Busan 49241, Korea E-mail: mirsaint@hanmail.net

• Received: July 1, 2025 • Revised: July 18, 2025 • Accepted: July 21, 2025

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

1,369 Views
49 Download

prev next

Full Article

Download PDF

NOTES
REFERENCES

See the article "Efficacy of multi-hole self‑expandable metallic stents versus partially covered self‑expandable metallic stents in patients with malignant distal biliary obstruction caused by unresectable pancreatic cancer: a retrospective comparative cohort study in Japan" on page 744.

Biliary decompression using self-expandable metal stents (SEMSs) is the cornerstone of palliation for malignant distal biliary obstruction (MDBO), particularly in patients with unresectable pancreatic cancer (PC) and biliary tract cancer. The clinical effectiveness of SEMSs is determined by long-term stent patency and risk of adverse events, including tumor ingrowth and stent migration. Fully covered SEMSs (FCSEMSs) are designed to prevent tumor ingrowth but are more susceptible to migration. Conversely, uncovered SEMSs (UCSEMSs) are more stable but allow tumor ingrowth, leading to recurrent biliary obstruction (RBO). The optimal balance between these competing risks has driven continual innovations in stent design, including flaps, flared ends, and multi-hole configurations.

In this issue of Clinical Endoscopy, Asada et al.¹ conducted a retrospective cohort study comparing a novel multi-hole SEMS (MHSEMS) with a conventional partially covered SEMS (PCSEMS) in 137 patients with MDBO due to unresectable PC. The two groups (MHSEMS, 43; PCSEMS, 94) showed no statistically significant differences in median time to RBO (318 vs. 460 days, p=0.17), overall survival, or adverse event rates. Notably, stent migration occurred in 0% of the patients in the MHSEMS group compared to 8.5% (8/94) in the PCSEMS group, although this difference was not statistically significant. Importantly, all attempted stent removal procedures were successful in the MHSEMS group (7/7), whereas only half were successful in the PCSEMS group (2/4), highlighting the meaningful advantage of removability.

MHSEMSs incorporate small side holes in a silicone-covered membrane to promote partial tissue embedment for anti-migration while preserving removability. This design aligns with current clinical needs as improving systemic therapies prolongs survival, thus increasing the likelihood of late-onset complications requiring stent exchange. However, in Asada et al.’s study,¹ the MHSEMS group exhibited a significantly higher rate of tumor ingrowth (7.1% vs. 1.1%, p=0.089), raising concerns that the side holes may act as entry points for malignant tissue. This observation is consistent with previous findings by Takeda et al.,² who reported tumor ingrowth through the side holes of the MHSEMSs.

In a recent propensity score-matched analysis by Kulpatcharapong et al.,³ which included 114 patients with unresectable MDBO, MHSEMSs demonstrated the longest mean stent patency (479 days) and the lowest RBO rate (21.1%), significantly outperforming UCSEMSs (patency, 306 days; RBO, 54.5%) and matching or exceeding FCSEMSs (patency, 353 days; RBO, 36.8%). The MHSEMS group also showed a significantly lower rate of tumor ingrowth than the UCSEMSs group (13.2% vs. 42.4%, p<0.005) and a lower rate of migration than the FCSEMSs group (2.6% vs. 15.8%, p=0.047). Importantly, second-generation MHSEMSs engineered with fewer side holes exhibited better patency and less tumor ingrowth, indicating that the side-hole density is a modifiable and clinically relevant design variable.

Other approaches to mitigate stent migration have focused on the mechanical anchoring features. Miyazawa et al.⁴ demonstrated that a dumbbell-shaped FCSEMS with flared ends achieved both high patency and full removability in patients with distal malignant biliary obstruction. Similarly, Park et al.⁵ showed that FCSEMSs with anchoring flaps resulted in a 0% migration rate in benign biliary strictures, whereas flared-end FCSEMSs exhibited a 33% migration rate, highlighting the superiority of flap-based anchoring. In another prospective study, Mangiavillano et al.⁶ reported that FCSEMSs equipped with a novel anchoring flap system achieved a low migration rate of 3.3% and a 93.7% removal success rate in patients with benign biliary diseases. More recently, Sakai et al.⁷ and Yamashige et al.⁸ evaluated novel FCSEMSs in MDBO. Although the exact migration rates were not always specified, both studies demonstrated that modern FCSEMS designs—such as reduced-diameter stents or improved covering systems—could offer favorable migration resistance and removability. These findings suggest that both flap and flare designs can effectively reduce stent migration, and that flare configurations may also enhance removability.

Although the present study did not directly compare MHSEMS with flap- or flare-based FCSEMSs, previous reports on such stents have demonstrated migration rates ranging from 3% to 33%, with varying degrees of removability and risk of tissue hyperplasia.⁴^-⁶ In this context, MHSEMS, with its hybrid structure relying on partial embedment through multiple side holes, may offer a comparable or even superior anti-migration effect while maintaining removability and minimizing tumor ingrowth. Asada et al.’s findings,¹ particularly the 0% migration rate and 100% stent removal success, suggest that MHSEMS represent a promising evolution in covered stent design for MDBO.

Collectively, these data support the clinical viability of MHSEMSs in patients with MDBO, especially when considering long-term stent removal. MHSEMSs demonstrated excellent safety, low migration, and favorable patency outcomes in both Asada et al.’s and Kulpatcharapong’s studies.¹^,³ Nevertheless, caution is warranted in patients with highly infiltrative tumors or mucin-producing cancers, where side-hole entry could compromise patency.

In conclusion, MHSEMSs provide a promising addition to the armamentaria for MDBO management. Their hybrid design addresses the key limitations of conventional stents and aligns with the current clinical demands for flexibility, durability, and procedural reversibility. Future investigations should further explore hole geometry refinements, assess cost-effectiveness, and establish optimal patient selection criteria for prospective studies.

Conflicts of Interest

The author has no potential conflicts of interest.

Funding

None.

REFERENCES

1. Asada S, Kitagawa K, Tomooka F, et al. Efficacy of multi-hole self‑expandable metallic stents versus partially covered self‑expandable metallic stents in patients with malignant distal biliary obstruction caused by unresectable pancreatic cancer: a retrospective comparative cohort study in Japan. Clin Endosc 2025;58:744–756.Article
2. Takeda T, Sasaki T, Okamoto T, et al. Outcomes of multi-hole self-expandable metal stents versus fully covered self-expandable metal stents for malignant distal biliary obstruction in unresectable pancreatic cancer. DEN Open 2024;5:e70014.Article PubMed PMC
3. Kulpatcharapong S, Piyachaturawat P, Mekaroonkamol P, et al. Efficacy of multi-hole self-expandable metal stent compared to fully covered and uncovered self-expandable metal stents in patients with unresectable malignant distal biliary obstruction: a propensity analysis. Surg Endosc 2024;38:212–221.Article PubMed PDF
4. Miyazawa M, Takatori H, Okafuji H, et al. Efficacy of a novel self-expandable metal stent with dumbbell-shaped flare ends for distal biliary obstruction due to unresectable pancreatic cancer. Sci Rep 2022;12:21100.Article PubMed PMC PDF
5. Park DH, Lee SS, Lee TH, et al. Anchoring flap versus flared end, fully covered self-expandable metal stents to prevent migration in patients with benign biliary strictures: a multicenter, prospective, comparative pilot study (with videos). Gastrointest Endosc 2011;73:64–70.Article PubMed
6. Mangiavillano B, Manes G, Baron TH, et al. The use of double lasso, fully covered self-expandable metal stents with new "anchoring flap" system in the treatment of benign biliary diseases. Dig Dis Sci 2014;59:2308–2313.Article PubMed PDF
7. Sakai A, Masuda A, Eguchi T, et al. A novel fully covered metal stent for unresectable malignant distal biliary obstruction: results of a multicenter prospective study. Clin Endosc 2024;57:375–383.Article PubMed PMC PDF
8. Yamashige D, Hijioka S, Nagashio Y, et al. Potential of 6-mm-diameter fully covered self-expandable metal stents for unresectable malignant distal biliary obstruction: a propensity score-matched study. Clin Endosc 2025;58:121–133.Article PDF

Figure & Data

REFERENCES

Citations

Citations to this article as recorded by

PubReader
ePub Link

Cite

CITE: export Copy Download Format; Close

Download Citation

Download a citation file in RIS format that can be imported by all major citation management software, including EndNote, ProCite, RefWorks, and Reference Manager.

Format: