Comparing the 14-mm uncovered and 10-mm covered metal stents in patients with distal biliary obstruction caused by unresectable pancreatic cancer: a multicenter retrospective study



Endoscopic biliary drainage using metal stent (MSs) is an established palliative treatment for patients with unresectable malignant distal biliary obstruction (MDBO). However, a major drawback of MS is recurrent biliary obstruction (RBO). Uncovered MSs with a diameter of 14 mm (UMS-14) were developed to overcome this. We aimed to compare the clinical outcomes of UMS-14 with those of conventional covered MSs having a diameter of 10 mm (CMS-10).


Consecutive patients with MDBO caused by unresectable pancreatic cancer, who underwent UMS-14 or CMS-10 placement at two tertiary-care centers, were retrospectively examined according to the Tokyo Criteria 2014.


Two hundred and thirty-eight patients who underwent UMS-14 (the UMS-14 group, n = 80) or CMS-10 (the CMS-10 group, n = 158) over a 62-month period were included. The technical and clinical success rates were similar between the two groups. RBO occurred in 20 (25%) and 59 (37%) patients of the UMS-14 and CMS-10 groups, respectively (p = 0.06). Median time till RBO was significantly longer in the UMS-14 group than in the CMS-10 group (not reached vs. 290 days, p = 0.04). Multivariate analysis revealed that CMS-10 placement was an independent risk factor for RBO (hazard ratio: 1.66, 95% confidence interval: 1.00–2.76). The incidence of early complications, including pancreatitis, and the overall survival (UMS-14 vs. CMS-10: 169 vs. 167 days, p = 0.83) were comparable between the two groups.


UMS-14 stents were safe and effective for treating patients with MDBO secondary to unresectable pancreatic cancer. The insertion of UMS-14 is recommended, because it is less likely to get occluded as compared to CMS-10.

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We thank all members of the Division of Endoscopy, Shizuoka Cancer Center, for the help rendered to this study.

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Correspondence to Hirotoshi Ishiwatari.

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Drs. Tatsunori Satoh, Hirotoshi Ishiwatari, Shinya Kawaguchi, Naofumi Shirane, Hiroyuki Matsubayashi, Junichi Kaneko, Junya Sato, Kazuma Ishikawa, Takuya Otsu, Shuzo Terada, Hiroyuki Ono, and Masataka Kikuyama have no conflicts of interest or financial ties to declare.

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Supplementary Fig. 1

Supplementary file2 (TIF 252 KB) Kaplan–Meier curve comparing the cumulative time to recurrent biliary obstruction (TRBO) between UMS-14 and Niti-S SUPREMO. The TRBO for UMS-14 was significantly longer than that for Niti-S SUPREMO (not reached vs. 260 days, p = 0.02, log-rank test).

Supplementary Fig. 2

Supplementary file3 (TIF 267 KB) Kaplan–Meier curve comparing the cumulative patient survival between UMS-14 and Niti-S SUPREMO. There are no significant differences in the patient survival between the two (169 days vs. 167 days, p = 0.88, log-rank test).

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Satoh, T., Ishiwatari, H., Kawaguchi, S. et al. Comparing the 14-mm uncovered and 10-mm covered metal stents in patients with distal biliary obstruction caused by unresectable pancreatic cancer: a multicenter retrospective study. Surg Endosc (2021).

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  • Biliary drainage
  • Metal stent
  • Pancreatic cancer
  • Malignant biliary obstruction
  • Large diameter stent