Partially covered metal stents have longer patency than uncovered and fully covered metal stents in the management of distal malignant biliary obstruction: a retrospective study

Computed tomography-based prediction of pancreatitis following biliary metal stent placement with the convolutional neural network

Background and study aims Pancreatitis is a potentially lethal adverse event of endoscopic transpapillary placement of a self-expandable metal stent (SEMS) for malignant biliary obstruction (MBO). Deep learning-based image recognition has not been investigated in predicting pancreatitis in this setting. Patients and methods We included 70 patients who underwent endoscopic placement of a SEMS for nonresectable distal MBO. We constructed a convolutional neural network (CNN) model for pancreatitis prediction using a series of pre-procedure computed tomography images covering the whole pancreas (≥ 120,960 augmented images in total). We examined the additional effects of the CNN-based probabilities on the following machine learning models based on clinical parameters: logistic regression, support vector machine with a linear or RBF kernel, random forest classifier, and gradient boosting classifier. Model performance was assessed based on the area under the curve (AUC) in the receiver operating characteristic analysis, positive predictive value (PPV), accuracy, and specificity. Results The CNN model was associated with moderate levels of performance metrics: AUC, 0.67; PPV, 0.45; accuracy, 0.66; and specificity, 0.63. When added to the machine learning models, the CNN-based probabilities increased the performance metrics. The logistic regression model with the CNN-based probabilities had an AUC of 0.74, PPV of 0.85, accuracy of 0.83, and specificity of 0.96, compared with 0.72, 0.78, 0.77, and 0.96, respectively, without the probabilities. Conclusions The CNN-based model may increase predictability for pancreatitis following endoscopic placement of a biliary SEMS. Our findings support the potential of deep learning technology to improve prognostic models in pancreatobiliary therapeutic endoscopy.

Therapeutic biliary stents: applications and opportunities

INTRODUCTION

Biliary stents are used to optimize ductal patency and enable bile flow in the management of obstruction or injury related to biliary tract tumors, strictures, stones, or leaks. Although direct therapeutic applications of biliary stents are less well developed, stents can be used to deliver drugs, radioisotopes, and photodynamic therapy.

AREAS COVERED

This report provides an in-depth overview of the clinical indications, and therapeutic utility of biliary stents. Unique considerations for the design of biliary stents are described. The properties and functionalities of materials used for stents such as metal alloys, plastic polymers, or biodegradable materials are described, and opportunities for design of future stents are outlined. Current and potential applications of stents for therapeutic applications for biliary tract diseases are described.

EXPERT OPINION

Therapeutic biliary stents could be used to minimize inflammation, prevent stricture formation, reduce infections, or provide localized anti-cancer therapy for biliary tract cancers. Stents could be transformed into therapeutic platforms using advanced materials, 3D printing, nanotechnology, and artificial intelligence. Whilst clinical study and validation will be required for adoption, future advances in stent design and materials are expected to expand the use of therapeutic biliary stents for the treatment of biliary tract disorders.

Fully covered versus partially covered self-expandable metal stents for palliation of distal malignant biliary obstruction: a systematic review and meta-analysis

BACKGROUND AND AIMS

Self-expandable metal stents (SEMSs) are standardly used for distal malignant biliary obstruction (dMBO). Although data suggest that covered versus uncovered SEMSs increase the time to recurrent biliary obstruction (TRBO), no data are available for fully covered (FC) versus partially covered (PC) designs.

METHODS

PubMed, Scopus, and Cochrane databases were screened up to January 2023 for studies concerning dMBO treated by an FC- or PC-SEMS and describing adverse events (AEs), recurrences, or TRBO for specific design subpopulations. Pooled proportions or means were calculated using a random-effects model. Several subanalyses were preplanned, including a subanalysis restricted to prospective studies and unresectable diseases. Heterogeneity and publication bias were explored. Standardized differences (d-values) were calculated between groups.

RESULTS

From 1290 records, 62 studies (3327 using FC-SEMSs and 2322 using PC-SEMSs) were included. FC- versus PC-SEMSs showed negligible differences in the rate of total AEs (12% vs 9.9%) and all specific AEs, including cholecystitis (2.5% vs 2.6%). In a subanalysis restricted to prospective studies and unresectable diseases, the rate of RBO was comparable between FC-SEMSs (27.3% [95% confidence interval {CI}, 23.7-31.2], I2 = 35.34%) and PC-SEMSs (25.3% [95% CI, 20.2-30.7], I2 = 85.09%), despite small differences (d-values between .186 and .216) in the rate of ingrowth (.5% vs 2.9%) favoring FC-SEMSs and migration (9.8% vs 4.3%) favoring PC-SEMSs. TRBO was shorter for FC-SEMSs (238 days [95% CI, 191-286], I2 = 63.1%) versus PC-SEMSs (369 days [95% CI, 290-449], I2 = 71.9%; d-value = .116).

CONCLUSIONS

Despite considerable heterogeneity and small standardized differences, PC-SEMSs consistently exhibited longer TRBO than FC-SEMSs across analyses, without any other differences in AE rates, potentially proposing PC-SEMSs as the standard comparator and TRBO as the primary outcome for future randomized studies on dMBO. (Clinical trial registration number: CRD42023393965.).

Factors associated with patency of self-expandable metal stents in malignant biliary obstruction

INTRODUCTION

Endoscopic self-expandable metal stent (SEMS) placement is the key endoscopic treatment for unresectable malignant biliary obstruction. The benefit of covered SEMS over uncovered SEMS remains unknown as are risk factors for SEMS dysfunction. This study aimed to determine the factors associated with patency of SEMS.

METHODS

Patients with unresectable malignant biliary obstruction who underwent endoscopic SEMS placement at Ramathibodi Hospital, during January 2012 to March 2021 were included. Patient characteristics, clinical outcomes and patency of SEMS were collected. The primary outcome were stent patency and factors associated with patency of SEMS. The factors were analyzed by univariate and multivariate analyses. Median days of stent patency, median time of patient survival, rate of reintervention and complications after SEMS placement were collected.

RESULTS

One hundred and fourteen patients were included. SEMS dysfunction was found in 37 patients (32.5%). Size of cancer (Hazard ratio (HR), 1.20, (95% CI 1.02, 1.40), p 0.025), presence of stones or sludge during SEMS placement (Hazard ratio (HR), 3.91, (95% CI 1.74, 8.75), p 0.001), length of SEMS, 8 cm (HR 2.96, (95% CI 1.06, 8.3), p 0.039), and total bilirubin level above 2 mg/dL at one month after SEMS placement (HR 1.14, (95% CI 1.06, 1.22), p < 0.001) were associated with SEMS dysfunction. The median stent patency was 97 days. The median patient survival was 133 days, (95% CI 75-165). The rate of reintervention was 86% in patients with SEMS dysfunction.

CONCLUSION

The size of cancer, presence of stones or sludge during SEMS placement, the length of SEMS, and total bilirubin level above 2 mg/dL at 1 month after SEMS placement were associated with SEMS dysfunction. The median time of stent patency were not statistically different in each type of stent, covered stent, partially covered stent and uncovered stent. Median survival time of patients did not associate with SEMS patency or dysfunction.

Uncovered versus fully covered self-expandable metal stents for the management of distal malignant biliary obstruction

BACKGROUND AND AIM

Self-expandable metal stents (SEMSs) are widely used for palliation of distal malignant biliary obstruction (dMBO). However, previous studies comparing the outcomes between uncovered SEMSs (UCSEMSs) and fully covered SEMSs (FCSEMSs) report conflicting results. This large cohort study aimed to compare the clinical outcomes between UCSEMSs and FCSEMSs for dMBO.

METHODS

A retrospective cohort study was performed in patients with dMBO who underwent either UCSEMS or FCSEMS placement between May 2017 and May 2021. Primary outcomes were rates of clinical success, adverse events (AEs), and unplanned endoscopic reintervention. Secondary outcomes were types of AEs, intervention-free stent patency, and management and outcomes of stent occlusion.

RESULTS

The cohort included 454 patients (364 in the UCSEMS group and 90 in the FCSEMS group). Median follow-up duration was 9.6 months and was similar between the 2 groups. Use of UCSEMSs and FCSEMSs had comparable clinical success (P = .250). However, use of UCSEMSs had significantly higher rates of AEs (33.5% vs 21.1%; P = .023) and unplanned endoscopic reintervention (27.0% vs 11.1%; P = .002). UCSEMSs had a higher rate of stent occlusion (26.9% vs 8.9%; P < .001) and shorter median time to stent occlusion (4.4 months vs 10.7 months; P = .002). Stent reintervention-free survival was higher in the FCSEMS group. FCSEMSs had a significantly higher rate of stent migration (7.8% vs 1.1%; P < .001), but patients in the FCSEMS group had similar rates of cholecystitis (.3% vs 1.1%; P = .872) and post-ERCP pancreatitis (6.3% vs 6.6%; P = .90). When UCSEMSs did occlude, placement of a coaxial plastic stent had a higher rate of stent reocclusion compared with coaxial SEMS placement (46.7% vs 19.7%; P = .007).

CONCLUSION

FCSEMSs should be considered for the palliation of dMBO because of lower rates of AEs, longer patency rates, and lower rates of unplanned endoscopic intervention.

Efficacy and safety of covered versus uncovered self‑expandable metal stents for the palliative treatment of malignant distal biliary stricture: A long‑term retrospective study

Both covered self-expandable metal stents (CSEMSs) and uncovered self-expandable metal stents (USEMSs) have been tried in the palliation of malignant distal biliary strictures by means of endoscopic retrograde cholangiopancreatography (ERCP); however, the comparison of efficacy and safety between them remains contested. To the best of our knowledge, no similar studies have assessed this in the Chinese population. In the present study, the clinical and endoscopic data of 238 patients (CSEMSs, n=55; USEMSs, n=183) with malignant distal biliary strictures from 2014 to 2019 were collected. The efficacy indicated by mean stent patency, stent patency rate, mean patient survival time and survival rate, and the safety indicated by adverse events after CSEMS or USEMS placement were retrospectively analyzed and compared. The mean stent patency time was significantly longer in the CSEMSs group than that in the USEMSs group (262.8±195.3 days vs. 169.5±155.7 days, P=0.002). The mean patient survival time was significantly longer in the CSEMSs group than that in the USEMSs group (273.9±197.6 days vs. 184.9±167.6 days, P=0.003). The stent patency rate and patient survival rate were significantly higher in the CSEMSs group than those in the USEMSs group at 6 and 12 months, but not at 1 and 3 months. There was no significant difference in stent dysfunction and adverse events between the two groups, although post-ERCP pancreatitis (PEP) occurred more frequently in the CSEMSs group than in the USEMSs group (18.1% vs. 8.8%, P=0.049). In conclusion, CSEMSs were better than USEMSs for malignant distal biliary strictures in terms of stent patency time and patient survival time as well as stent patency rate and patient survival rate in the long term (>6 months). Adverse events in the two groups occurred at a similar rate, although the incidence of PEP was higher in the CSEMSs group.

Efficacy of a novel self-expandable metal stent with dumbbell-shaped flare ends for distal biliary obstruction due to unresectable pancreatic cancer

This study aimed to evaluate the efficacy of a novel fully covered self-expandable metal stent (SEMS) with dumbbell-shaped flare ends for the palliation of distal biliary obstruction (DBO) due to unresectable pancreatic cancer (UPC). Patients with DBO due to UPC who received the novel HILZO fully covered stent (HFS), the WALLFLEX partially covered stent (WPS) or fully covered stent (WFS) were analyzed. The incidence of recurrent biliary obstruction (RBO), time to RBO (TRBO), and the incidence of complications were compared among the three SEMS groups. Eighty-four patients (HFS, n = 36; WPS, n = 20; WFS, n = 28) were included. The incidence of RBO was low in the HFS group (versus the WPS and WFS group, p = 0.033 and 0.023, respectively). TRBO in the HFS group was longer than that in the WFS group (p = 0.049). Placement of the HFS was an independent factor for long TRBO in multivariable analysis (p = 0.040). The incidence of pancreatitis and cholecystitis in the HFS group was low (one for each). It is recommended to use the HFS for the palliation of DBO due to UPC from the viewpoint of the low incidence of RBO and complications.

Factors related to stent patency and early elimination of jaundice using bile duct stent combined with iodine-125 seed implantation in malignant obstructive jaundice

Purpose

Biliary stents combined with percutaneous or endoscopic ultrasound-guided iodine-125 seed implantation into primary tumor have been confirmed to relieve malignant obstructive jaundice (MOJ), and prolong patient's stent patency. The aim of the study was to evaluate meaningful clinical application indications and better guide the application of this technology.

Material and methods

Patients with MOJ, who have received bile duct stenting combined with iodine-125 (¹²⁵I) seed implantation from October, 2010 to April, 2022, were retrospectively analyzed. Univariate and multivariate analyses were adopted to indicate factors of stent patency in MOJ and influencing factors of jaundice reduction at one week after surgery.

Results

A total of 90 patients were enrolled into the study, including 52 males (57.8%) and 38 females (42.2%), with a mean age of 68.66 ±12.53 years. The median stent patency was 8 months. No serious adverse events occurred during follow-up. Multivariate analysis showed that Child-Pugh score (HR = 2.221, 95% CI: 1.081-4.562), biliary infection (HR = 1.901, 95% CI: 1.084-3.335), and pre-operative jaundice duration (HR = 1.977, 95% CI: 1.106-3.533) were the independent risk factors for stent patency. Child-Pugh B/C (OR = 4.647, 95% CI: 1.080-19.982) and bile duct infection (OR = 3.583, 95% CI: 1.095-11.725) were the independent risk factors for jaundice reduction at one week after surgery.

Conclusions

MOJ patients treated with biliary stents combined with ¹²⁵I seed implantation, and patients with better pre-operative liver function and no biliary tract infection, present not only longer biliary stent patency, but also better early jaundice reduction.

Acetylsalicylic acid for metal stent in malignant distal common bile duct obstruction: A randomized controlled trial

BACKGROUND

Endoscopic biliary drainage is the treatment of choice for patients with malignant distal common bile duct obstruction. Self-expandable metal stents have clinical advantages including an increased duration of patency that may be prolonged by acetylsalicylic acid (ASA) use. The aim of this study was to investigate whether ASA had a positive effect on the patency of self-expandable metal stents compared with placebo.

METHODS

This prospective, multicenter, double-blinded, and randomized placebo-controlled trial was conducted from October 2017 to May 2020 in Korea. Patients who underwent palliative endoscopic biliary drainage with self-expandable metal stents for malignant distal bile duct obstruction were enrolled, and allocated to ASA treatment or placebo. The study outcomes were the rate of stent dysfunction at 6 months, duration of stent patency, risk factors for stent dysfunction, and any adverse events.

RESULTS

Interim analysis included 24 and 28 patients in the ASA and placebo groups, respectively. There was no significant difference between the ASA and placebo groups in stent dysfunction (25.0% vs. 20.7%, P = 0.761) or the duration of stent patency (150.97 ± 10.55 vs. 158.07 ± 8.70 days, P = 0.497). Six patients experienced suspected ASA-related adverse events, and there was one lethal case.

CONCLUSIONS

ASA did not prolong stent patency. This study was terminated early because of the possibility of serious adverse events related to ASA treatment of these patients receiving palliative care.

Jailbreaking a metal biliary stent through a duodenal stent

Video 1.

Prevention of Serious Complications during Endoscopic Ultrasound-Guided Biliary Drainage: A Case-Based Technical Review

Endoscopic ultrasound-guided biliary drainage (EUS-BD) has a potential risk of clinically significant adverse events including fatal complications. Learning from complications improves the results from interventional procedures especially the high-risk procedure like EUS-BD. The various complications that have been reported following EUS-BD include bile leak, bleeding, cholangitis, peritonitis, stent migration both internal and external as well as in the peritoneal cavity and fatal perforations. In this technical review, we discuss technical strategies to prevent serious adverse events during EUS-BD using a case based approach.

Risk factors for biliary stent infections in malignant biliary obstruction secondary to unresectable malignancies

BACKGROUND

Palliative biliary drainage in patients with unresectable malignant biliary obstruction (MBO) frequently leads to biliary stent infection (BI), which could impact medical care. The aim of this study was to assess the risk factors for BI occurrence in patients after stenting procedure and the impact of BI on patient survival.

METHODS

All consecutive patients hospitalized from 2014 to 2018 for MBO and biliary stenting were retrospectively included. Demographic, clinical, and microbiological characteristics of each BI episode during a 1-year follow-up were described. Documented BI was defined as the association of BI episode and confirmed blood stream infection (BSI). Univariate and multivariate analyses were performed to evaluate risk factors for the first BI occurrence.

RESULTS

Among 180 patients, 56% were men (mean age of 69±12), and 54% have pancreatic cancer, 16% biliary cancer, 2% hepatic cancer, and 28% lymph node or metastatic compression; metallic stent was placed in 92%. A total of 113 BI episodes occurred in 74 patients, 55% of the first episodes occurring within 3 months after stenting. BI was documented in 56% of the episodes. Enterobacteriaceae were the most frequent pathogens found, while no yeasts were documented. Mortality rate in patients with BI was 64%. Multivariate analysis showed a significant difference in BI occurrence for two criteria: WHO score 3-4 (OR=8.79 [1.79-42.89]; p=0.007) and transpapillary stenting location (OR=3.72 [1.33-10.44]; p=0.013).

CONCLUSION

Since transpapillary stenting is a risk factor for BI, preserving the papilla as much as possible is a priority so as to avoid BI.

Laser-cut-type versus braided-type covered self-expandable metallic stents for distal biliary obstruction caused by pancreatic carcinoma: a retrospective comparative cohort study

BACKGROUND/AIMS

Covered self-expandable metallic stents (CMSs) are widely used for malignant distal biliary obstructions (MDBOs) caused by pancreatic carcinoma. This study compared the efficacy and safety of the laser-cut-type and braided-type CMSs.

METHODS

To palliate MDBOs caused by pancreatic carcinoma, the laser-cut-type CMSs was used from April 2014 to March 2017, and the braided-type CMSs was used from April 2017 to March 2019. The tested self-expandable metallic stents were equipped with different anti-migration systems.

RESULTS

In total, 47 patients received CMSs for MDBOs (24 laser-cut type, 23 braided-type). The time to recurrent biliary obstruction (TRBO) was significantly longer in the braided-type CMSs (p=0.0008), and the median time to stent dysfunction or patient death was 141 and 265 days in the laser-cut-type CMSs and braided-type CMSs, respectively (p=0.0023). Stent migration was the major cause of stent dysfunction in both groups, which occurred in 37.5% of the laser-cut-type CMSs and 13.0% of the braidedtype CMSs. There were no differences in the survival duration between the groups.

CONCLUSION

The TRBO was significantly longer for the braided-type CMSs with an anti-migration system than for the laser-cuttype. Stent migration tended to be less frequent with the braided-type CMSs than with the laser-cut-type CMSs.

Prevention of pancreatitis after stent implantation for distal malignant biliary strictures: systematic review and meta-analysis

INTRODUCTION

Biliary stent placement remains a palliative treatment for patients with unresectable distal malignant biliary strictures (DMBS). The incidence of post-ERCP-pancreatitis (PEP) significantly increases in patients receiving fully covered self-expandable metal stents (FCSEMS) who undergo endoscopic retrograde cholangiopancreatography (ERCP).

AREAS COVERED

This review provides an overview of prevention of PEP after stent implantation for DMBSs. The following operational variables were evaluated: (1) stent type (plastic or metal stent); (2) stent location (above or across the sphincter of Oddi); (3) prophylactic pancreatic duct stent placement; (4) endoscopic sphincterotomy (EST). PubMed, EMBASE, and Cochrane database were searched to identify eligible studies up to October 2021. The odds ratio (OR) with 95% confidence intervals (CI) were pooled using fixed- or random- effects models.

EXPERT OPINION

1. PEP occurs more frequently in DMBS patients with self-expandable metal stents (SEMS) compared to that plastic stent (PS). 2. The PEP incidence is higher in covered stents than that in uncovered self-expandable metal stents (USEMS), but not significantly. 3. PEP incidence increases in patients receiving transpapillary FCSEMS placement, particularly when there is an absence of pancreatic duct dilation, and prophylactic pancreatic stenting is recommended for these patients. 4. Limited studies with small sample indicate that there is no significant difference in PEP incidence between transpapillary and suprapapillary stents placement for DMBS. 5. Limited studies indicate that EST does not significantly affect the incidence of pancreatitis in DMBS patients.

Plastic or self-expandable metal stent: Which is the most suitable for patients with pancreatic head cancer in the upcoming era of neoadjuvant chemotherapy? A review

Obstructive jaundice is a major symptom of pancreatic head cancer, and although its amelioration is required before scheduling chemotherapy, the decision to perform biliary drainage for resectable pancreatic cancer has remained controversial. In recent years, the effectiveness of neoadjuvant therapy for pancreatic cancer has been reported. Preoperative biliary drainage has become increasingly necessary, making the choice of stent an important one; thus, the longer the waiting period extends through neoadjuvant chemotherapy, the more durable stents - such as self-expandable metallic stents, rather than plastic stents - would be desired as an option. Still, there is insufficient evidence regarding surgical outcomes and long-term prognosis, and further confirmatory studies are needed. Through this review, we aim to provide an update on the characteristics of biliary stents and preoperative biliary drainage for potentially resectable pancreatic cancer.

Can the laser-cut covered self-expandable metallic stent be the first choice for patients with unresectable distal malignant biliary obstruction? (with video)

OBJECTIVES

To evaluate whether laser-cut covered self-expandable metallic stents (LC-CSEMSs) can be the first choice for patients with unresectable distal malignant biliary obstruction (DMBO).

METHODS

Patients with unresectable DMBO who received LC-CSEMS (September 2014-December 2020) or braided CSEMS (B-CSEMS) (July 2013-December 2020) placement for biliary drainage were enrolled. Outcomes, including endoscopic CSEMS removal, of LC-CSEMSs and B-CSEMSs were compared.

RESULTS

Overall, 124 patients received LC-CSEMSs placement, and 121 B-CSEMSs. Technical success, clinical success, and procedure-related adverse event rates with LC-CSEMSs were 100%, 96.8%, and 6.5%, respectively, and 100%, 95.9%, and 5.8%, respectively, for B-CSEMSs, with no significant difference (P > .99, .75, and >.99, respectively). The recurrent biliary obstruction (RBO) rates with LC-CSEMSs and B-CSEMSs were 9.7% (12/124) and 13.2% (16/121), respectively (P = .43). The median time to RBO with LC-CSEMSs and B-CSEMSs was 198 (interquartile range [IQR], 124-244) days and 191 (IQR, 106-271) days (P = .41). The endoscopic removal success rates of LC-CSEMSs and B-CSEMSs were 88.9% (8/9) and 90% (9/10) (P > .99), although there were a small number of cases.

CONCLUSIONS

The non-inferiority of LC-CSEMSs was proven. LC-CSEMSs can be considered as the first choice for patients with unresectable DMBO.

Trial protocol: a randomised controlled trial to verify the non-inferiority of a partially covered self-expandable metal stent to an uncovered self-expandable metal stent for biliary drainage during neoadjuvant therapy in patients with pancreatic cancer with obstructive jaundice (PUN-NAC trial)

INTRODUCTION

Neoadjuvant chemotherapy or neoadjuvant chemoradiotherapy (NAC/NACRT) for resectable/borderline resectable pancreatic cancers was recently performed to improve clinical outcomes and led to good results, although it remains controversial whether NAC/NACRT is beneficial for resectable pancreatic cancer. A few recent studies revealed longer patency and lower cost related to the stent occlusion of a metal stent than those of a plastic stent during NAC/NACRT. It also remains controversial which type of self-expandable metal stent (SEMS) is the most suitable for patients with resectable/borderline resectable pancreatic cancer during NAC/NACRT: an uncovered SEMS (USEMS), a fully covered SEMS (FCSEMS) or a partially covered SEMS (PCSEMS). So far, two randomised controlled trials indicated that a USEMS and an FCSEMS were similar in preoperative stent dysfunction and adverse event rate. Thus, we aimed to verify the non-inferiority of a PCSEMS to a USEMS in this multicentre randomised controlled trial.

METHODS AND ANALYSIS

We designed a multicentre randomised controlled trial, for which we will recruit 100 patients with resectable/borderline resectable pancreatic cancer and distal biliary obstruction scheduled for NAC/NACRT from 13 high-volume institutions. Patients will be randomly allocated to the PCSEMS group or USEMS group. The primary outcome measure is the preoperative biliary event rate. Data will be analysed after completion of the study. We will calculate the 95% CIs of the incidence of preoperative biliary events in each group and analyse whether the difference between them is within the non-inferiority margin (10%).

ETHICS AND DISSEMINATION

This study has been approved by the institutional review board of Hokkaido University Hospital. The results will be submitted for presentation at an international medical conference and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

UMIN000041737; jRCT1012200002.

Stent Insertion With High Intensity-Focused Ultrasound Ablation for Biliary Obstruction Caused by Pancreatic Carcinoma: A Randomized Controlled Trial

PURPOSE

This study was designed to assess the clinical efficacy of stent insertion with high intensity-focused ultrasound ablation (HIFUA) in patients with malignant biliary obstruction (MBO) as a consequence of pancreatic carcinoma (PC).

MATERIALS AND METHODS

This was a single-center, open-label, prospective, randomized controlled trial. Consecutive patients with MBO caused by PC were randomly assigned to undergo stent insertion with or without HIFUA from June 2019 to February 2020. This study was registered at ClinicalTrials.gov (NCT03962478).

RESULTS

In total, 92 patients were enrolled in this study and assigned to the stent-only (n=46) or combined (stent+HIFUA; n=46) treatment groups. Stent insertion was associated with a 100% technical success rate. For patients in the combination treatment group, 26, 18, and 2 patients underwent 2, 3, and 4 cycles of HIFUA, respectively. A positive clinical response to HIFUA treatment was noted in 38 patients (82.6%). Stent dysfunction was detected in 9 and 15 patients in the combination and stent-only groups, respectively (P=0.154), while median stent patency in these 2 groups was 188 and 120 days, respectively (P<0.001). All patients died over the course of the follow-up, with median survival periods of 218 and 140 days in the combination and stent-only treatment groups, respectively (P=0.001). The only detected predictor of prolonged survival was HIFUA treatment (P=0.004), and there were no significant differences in complication rates between these 2 treatment groups.

CONCLUSION

A combination of stent insertion and HIFUA can improve stent patency and overall survival in patients suffering from MBO because of PC relative to stent insertion alone.

Stent performance in palliative transhepatic treatment of malignant biliary obstruction: a randomized study comparing covered versus uncovered stents

BACKGROUND

Considering the limitations in both uncovered self-expandable metallic stents (USEMS) and covered self-expandable metallic stents (CSEMS), it is difficult to make a general recommendation for their application in percutaneous decompression of malignant biliary obstruction (MBO).

PURPOSE

To compare percutaneous transhepatic CSEMSs versus USEMSs for the palliative treatment of MBO in terms of technical success, clinical success, stent patency, patient survival, complications, and stent dysfunction.

MATERIAL AND METHODS

This prospective randomized study included 66 patients with unresectable MBO. CSEMSs were inserted in 31 patients (26 men, 5 women; mean age = 63.8 ± 7.96 years) and USEMSs were inserted in 35 patients (26 men, 9 women; mean age = 62.3 ± 11.7 years).

RESULTS

Mean primary stent patency duration was 138 ± 92.7 days in CSEMSs versus 150 ± 77.9 days in USEMSs (P = 0.578). Tumor overgrowth occurred exclusively in one patient with CSEMS (P = 0.470) and tumor ingrowth exclusively in two patients with USEMS (P = 0.494). Stent migration occurred in two patients with CSEMSs versus one patient with USEMSs (P = 0.579). Hemobilia occurred in five patients with CSEMSs versus three patients with USEMSs while bile leakage occurred in one patient in each group despite the larger introducer sheath caliber with CSEMSs (9 F vs. 6-7 F). There was no significant difference regarding patient survival (P = 0.969).

CONCLUSION

In our cohort of patients with rather poor life expectancy, there was no significant difference between covered and uncovered stents for the palliative treatment of MBO. However, considering the higher cost of CSEMs and the larger introducer diameter necessary for their placement, USEMSs can be preferred.

Folfirinox chemotherapy prolongs stent patency in patients with malignant biliary obstruction due to unresectable pancreatic cancer

BACKGROUND

Stent insertion for biliary decompression to relieve jaundice and subsequent biliary infection is necessary for patients with biliary obstruction caused by pancreatic cancer, and it is important to keep the stent patent as long as possible. However, few studies have compared stent patency in terms of chemotherapy in patients with pancreatic cancer. This study aimed to evaluate the differences in stent patency in terms of recently evolving chemotherapy.

METHODS

Between January 2015 and May 2017, 161 patients with pancreatic cancer who had undergone biliary stent insertion with a metal stent were retrospectively analyzed. The relationship between chemotherapy and stent patency was assessed. Additionally, overall survival according to the treatment, risk factors for stent patency, and long-term adverse events were evaluated.

RESULTS

Median stent patency was 42 days for patients with the best supportive care and 217 days for patients with chemotherapy (conventional gemcitabine-based chemotherapy and folfirinox) (P < 0.001). Furthermore, the folfirinox group showed the longest median stent patency and overall survival, with 283 days and 466 days, respectively (P < 0.001) despite higher adverse events rate. Patients who underwent folfirinox chemotherapy after stent insertion had better stent patency in multivariate analysis (HR = 0.26; 95% CI: 0.12-0.60; P = 0.001).

CONCLUSIONS

Compared with patients who received best supportive care only, patients who underwent chemotherapy after stent insertion had better stent patency. More prolonged stent patency can be expected for patients with folfirinox than conventional gemcitabine-based chemotherapy.

Usefulness of half-covered metallic stent placement in preventing acute cholecystitis complication in pancreatic cancer-induced distal biliary stricture

Background and Aim

A self-expandable metallic stent (SEMS) is commonly used for biliary stricture caused by pancreatic cancer. Covered SEMS may obstruct the cystic duct, causing acute cholecystitis. This study aimed to determine the outcomes of using a half-covered SEMS with an offset covered portion for preventing cystic duct obstruction.

Methods

Among 80 patients with half-covered SEMS placement for the treatment of pancreatic cancer-induced distal biliary stricture, 74 were followed up. The half-covered SEMS has a total length of 6 or 7 cm, and the offset covered part was 0.5-4.5 or 0.5-5.5 cm, respectively. Intraductal ultrasonography (IDUS) and endoscopic nasobiliary drainage (ENBD) were performed during the initial endoscopic retrograde cholangiopancreatography (ERCP). IDUS findings and ENBD tube cholangiogram confirmed the cystic duct confluence. SEMS placement was performed on the second ERCP or several weeks after the initial tube stent placement.

Results

Half-covered SEMS placement was successful in all patients. However, four (5.4%) patients exhibited early complications, including acute cholecystitis in one patient and stent displacement in another. Over 30 days, cholangitis, tumor growth, and stent displacement occurred in nine (11.3%), five (6.3%), and two (2.5%) patients, respectively. The median stent patency was 71.1 weeks, and the median overall survival in patients with and without chemotherapy was 31.8 and 12.2 weeks, respectively.

Conclusions

With confirmation of the cystic duct confluence, half-covered SEMS placement may become a treatment option for distal biliary stricture caused by pancreatic cancer to prevent acute cholecystitis. Half-covered SEMS patency was comparable with that of covered SEMS.

Current Endoscopic Management of Malignant Biliary Stricture

Biliary and pancreatic cancers occur silently in the initial stage and become unresectable within a short time. When these diseases become symptomatic, biliary obstruction, either with or without infection, occurs frequently due to the anatomy associated with these cancers. The endoscopic management of these patients has changed, both with time and with improvements in medical devices. In this review, we present updated and integrated concepts for the endoscopic management of malignant biliary stricture. Endoscopic biliary drainage had been indicated in malignant biliary obstruction, but the concept of endoscopic management has changed with time. Although routine endoscopic stenting should not be performed in resectable malignant distal biliary obstruction (MDBO) patients, endoscopic biliary drainage is the treatment of choice for palliation in unresectable MDBO patients. Self-expanding metal stents (SEMS) have better stent patency and lower costs compared with plastic stents (PS). For malignant hilum obstruction, PS and uncovered SEMS yield similar short-term outcomes, while a covered stent is not usually used due to a potential unintentional obstruction of contralateral ducts.

Stent insertion with high-intensity focused ultrasound ablation for distal biliary obstruction secondary to pancreatic carcinoma

We determined the clinical effectiveness and long-term outcomes in patients with distal biliary obstruction (DBO) secondary to pancreatic carcinoma (PC) who were treated by self-expanded metallic stent (SEMS) insertion with or without high-intensity focused ultrasound (HIFU) ablation.From January 2014 to December 2018, consecutive patients with DBO secondary to PC underwent SEMS insertion with or without HIFU ablation in our center. The long-term outcomes were compared between the 2 groups.During the included period, 75 patients underwent SEMS insertion with (n = 34) or without (n = 41) HIFU ablation in our center. SEMS insertion was successfully performed in all patients. Liver function was significantly improved after SEMS insertion in both groups. An average of 2.9 HIFU treatment sessions per patient were performed. Twenty patients (stent + HIFU group: 7; stent-only group: 13) experienced stent dysfunction (P = .278). The clinical response rate to HIFU ablation was 79.4%. The median stent patency was significantly longer in the stent with HIFU group than in the stent-only group (175 vs 118 days, P = .005). The median survival was significantly longer in the stent with HIFU group compared with the stent-only group (211 versus 136 days, P = .004). An Eastern Cooperative Oncology Group (ECOG) Performance Status of 3 (hazard ratio: 0.300; P = .002) and subsequent HIFU ablation (hazard ratio: 0.508; P = .005) were associated with prolonged survival.HIFU ablation following stent insertion can prolong the stent patency and survival for patients with DBO secondary to PC.

Biomaterials in Gastroenterology: A Critical Overview

In spite of the large diversity of diagnostic and interventional devices associated with gastrointestinal endoscopic procedures, there is little information on the impact of the biomaterials (metals, polymers) contained in these devices upon body tissues and, indirectly, upon the treatment outcomes. Other biomaterials for gastroenterology, such as adhesives and certain hemostatic agents, have been investigated to a greater extent, but the information is fragmentary. Much of this situation is due to the paucity of details disclosed by the manufacturers of the devices. Moreover, for most of the applications in the gastrointestinal (GI) tract, there are no studies available on the biocompatibility of the device materials when in intimate contact with mucosae and other components of the GI tract. We have summarized the current situation with a focus on aspects of biomaterials and biocompatibility related to the device materials and other agents, with an emphasis on the GI endoscopic procedures. Procedures and devices used for the control of bleeding, for polypectomy, in bariatrics, and for stenting are discussed, particularly dwelling upon the biomaterial-related features of each application. There are indications that research is progressing steadily in this field, and the establishment of the subdiscipline of "gastroenterologic biomaterials" is not merely a remote projection. Upon the completion of this article, the gastroenterologist should be able to understand the nature of biomaterials and to achieve a suitable and beneficial perception of their significance in gastroenterology. Likewise, the biomaterialist should become aware of the specific tasks that the biomaterials must fulfil when placed within the GI tract, and regard such applications as both a challenge and an incentive for progressing the research in this field.

Predictors of stent occlusion in patients with unresectable pancreatic cancer after biliary metal stents

BACKGROUND

Self-expandable metal stents (SEMS) are a widely accepted biliary endoprosthesis for patients with unresectable malignant biliary obstruction. Here, we identified predictors for the occlusion of SEMS in unresectable pancreatic cancer patients with biliary tract obstruction.

METHODS

Patients with a distal malignant biliary obstruction caused by unresectable pancreatic cancer who received partially covered SEMS (PC-SEMS) placement for the first time between January 2003 and January 2016 were retrospectively enrolled for analysis. The rates of PC-SEMS occlusion were evaluated. The possible predictors of PC-SEMS occlusion were analyzed using Cox regression analysis.

RESULTS

In total, 120 patients who received PC-SEMS for unresectable pancreatic cancer were identified. The rate of PC-SEMS occlusion was 37%. The median time to occlusion of PC-SEMS was 359 days. The major causes of occlusion included biliary sludge (61%) and tumor ingrowth (30%). Cox multivariate regression analysis revealed that inadequate alkaline phosphatase/gamma-glutamyl transferase decline (defined by a decrease of <50% within 2 wk after PC-SEMS placement) was the only independent predictor of stent occlusion (hazard ratio, 2.86; 95% CI, 1.28-6.25; p = 0.01) CONCLUSION:: Inadequate alkaline phosphatase/gamma-glutamyl transferase decline is a predictor of occlusion of first-time PC-SEMS placement in unresectable pancreatic cancer patients with biliary tract obstruction.

Preliminary clinical application of integrated 125I seeds stents in the therapy of malignant lower biliary tract obstruction

PURPOSE

To evaluate the clinical efficacy of percutaneous trans-hepatic integrated 125I seed stents implantation for malignant lower biliary tract obstruction.

METHODS

Thirty-two patients with malignant lower biliary obstruction were randomly divided into two groups. One group underwent the therapy with integrated 125I seed stents (Test group, n = 13), and another group received conventional metal stents implantation for treatment (Control group, n = 19). The pre- and post-operative changes in biochemical indices, white blood cell count, IgG level, stent patency, survival time, tumor size and complications were compared between the two groups. RECIST 1.1 (Response Evaluation Criteria In Solid Tumors) was used to evaluate therapeutic effects. The average follow-up time was 12.3 months.

RESULTS

The differences between pre- and post-operative (30 days) intragroup biochemical indices had statistically significant difference (P < 0.05), but there were no significant differences (P > 0.05) in leukocyte counts and IgG levels. As to the median time of stent patency and patients' survival, there were significant differences (P < 0.05) between Control and Test groups (3.9 months vs. 8.1 months, 139 days vs. 298 days, respectively). Three months after the operation, the average tumor size was reduced in the Test group, but was increased in the Control group (P < 0.05). There was no significant difference in the incidence of complications between the two groups. The evaluation results using RECIST 1.1 showed that there were statistically significant differences between the two groups in terms of the rates of remission, control, and progression (χ2 = 17.5, P < 0.05).

CONCLUSIONS

The study indicates that integrated 125I seed stents are effective in reducing jaundice symptoms, inhibiting tumor growth, improving stent patency and prolonging patient survival, which may serve as a safer and more feasible method in treating malignant lower biliary obstruction with minimal invasiveness.