Paclitaxel-eluting covered metal stents versus covered metal stents for distal malignant biliary obstruction: a prospective comparative pilot study

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.

Advances in functional coatings on biliary stents

Biliary stenting is an important interventional method for the prevention and treatment of biliary tract diseases. However, complications, such as postoperative biliary infection and restenosis, frequently occur due to the extensive scope of the biliary system and the complex composition of bile. The combination of coating technology and biliary stents is expected to bring new approaches to the solution of these problems. The cutting-edge advance on functional coatings on biliary stents is reviewed from seven perspectives: anticorrosion, -bacterial, -tumor, stone-dissolving, X-ray visibility, antistent migration and functional composite coatings. The development trend is also discussed. Overall, the performance of the numerous functional coatings for various purposes is generally up to expectations, but the balance between the medications' effectiveness and their safety needs to be further adjusted. Many contemporary investigations have advanced to the level of animal experiments, offering crucial fundamental assurance for broader human studies. The combination of biliary stents and functional coatings is an innovative idea with great potential for future development.

A superlattice composite of Zn-Fe layered double hydroxide and graphene oxide for antitumor application

A superlattice composite of Zn-Fe layered double hydroxide and graphene oxide was fabricated on the titanium surface and showed lamellar morphology. It was found for the first time that this superlattice composite could inhibit cell adhesion and proliferation, and cause cell death of the cholangiocarcinoma cell line RBE cells in vitro and show tumor inhibition effect in vivo.

Endoscopic Management of Pancreatobiliary Malignancies

Pancreatobiliary malignancies have poor prognosis, and many patients are inoperable at the time of diagnosis. When surgical resection is impossible, systemic chemotherapy or radiotherapy is traditionally conducted with trial of immunotherapy or gene therapy lately. With the rapid development of endoscopic instruments and accessories in recent years, not only endoscopic early detection, characterization, and staging but also endoscopic palliative management of the pancreatobiliary malignancies is expanding the horizons. Endoscopic management is often preferred due to similar efficacy to surgical management with less morbidity. Here, we review the methodology and treatment outcome of various endoscopic management strategies in pancreatobiliary malignancies including endoscopic complication management, local palliative therapy, endoscopy-assisted therapy, and pain control utilizing endoscopic retrograde cholangiopancreatography or endoscopic ultrasound.

Futuristic Developments and Applications in Endoluminal Stenting

Endoscopic stenting is a well-established option for the treatment of malignant obstruction, temporary management of benign strictures, and sealing transmural defects, as well as drainage of pancreatic fluid collections and biliary obstruction. In recent years, in addition to expansion in indications for endoscopic stenting, considerable strides have been made in stent technology, and several types of devices with advanced designs and materials are continuously being developed. In this review, we discuss the important developments in stent designs and novel indications for endoluminal and transluminal stenting. Our discussion specifically focuses on (i) biodegradable as well as (ii) irradiating and drug-eluting stents for esophageal, gastroduodenal, biliary, and colonic indications, (iii) endoscopic stenting in inflammatory bowel disease, and (iv) lumen-apposing metal stent.

Indian College of Radiology and Imaging Evidence-Based Guidelines for Percutaneous Image-Guided Biliary Procedures

Percutaneous biliary interventions are among the commonly performed nonvascular radiological interventions. Most common of these interventions is the percutaneous transhepatic biliary drainage for malignant biliary obstruction. Other biliary procedures performed include percutaneous cholecystostomy, biliary stenting, drainage for bile leaks, and various procedures like balloon dilatation, stenting, and large-bore catheter drainage for bilioenteric or post-transplant anastomotic strictures. Although these procedures are being performed for ages, no standard guidelines have been formulated. This article attempts at preparing guidelines for performing various percutaneous image-guided biliary procedures along with discussion on the published evidence in this field.

Drug Eluting Versus Covered Metal Stents in Malignant Biliary Strictures-Is There a Clinical Benefit?: A Systematic Review and Meta-Analysis

GOALS/BACKGROUND

Patients with malignant biliary obstruction (MBO) often require transpapillary stenting for symptomatic relief and biliary decompression. Plastic stents and uncovered metal stents are now replaced by covered self-expanding metal stents (SEMS). However, stent occlusion from tumor overgrowth and chronic inflammation continues to be an issue. Drug-eluting stents (DES), through an antitumor paclitaxel membrane, have been used to combat this problem. The aim of this study was to conduct a meta-analysis comparing DES to SEMS in MBO.

STUDY

Multiple databases were searched to identify studies that compared the clinical outcomes of SEMS and DES in patients with MBO. Random-effects model was used to calculate the pooled odds ratio and the pooled individual outcomes. Our primary goals were to assess the stent patency and overall survival in days. Secondary outcomes assessed the individual reported adverse events and/or complications.

RESULTS

Five studies including 348 patients (175 males and 173 females) were included. The pooled odds ratio of stent patency was 1.03 (95% confidence interval: 0.68-1.54, P=0.9) and overall survival was 1.16 (95% confidence interval: 0.63-2.11, P=0.6). The pooled rate of stent patency was 168.3 (95% 140.7-196.4) days for DES and 149.4 (117.6-181.2) days for SEMS. The pooled rate of overall survival was 267.2 (206.2-328.2) days for DES and 218.2 (148.5-287.8) days for SEMS.

CONCLUSION

On the basis of this meta-analysis, DES and SEMS seem to demonstrate comparable clinical outcomes in patients with malignant biliary strictures. Reported adverse events and/or complications were comparable as well.

Biliary stent combined with iodine-125 seed strand implantation in malignant obstructive jaundice

BACKGROUND

Malignant obstructive jaundice is mainly caused by cholangiocarcinoma. Only a few patients are indicated for surgical resection, and the 3-year survival rate is < 50%. For patients who are not eligible for surgery, biliary stent placement can relieve biliary obstruction and improve liver function and quality of life. However, restenosis after biliary stents has a poor prognosis and is a clinical challenge. Biliary stent combined with iodine-125 (¹²⁵I) seed implantation can prolong stent patency and improve survival.

AIM

To evaluate the safety and efficacy of biliary stent combined with ¹²⁵I seed strand implantation in malignant obstructive jaundice.

METHODS

We enrolled 67 patients between January 2016 and June 2018 with malignant obstructive jaundice and randomized them into a biliary stent combined with ¹²⁵I seed strand treatment (combined) group (n = 32) and biliary stent (control) group (n = 35). All patients underwent enhanced computed tomography and magnetic resonance imaging and were tested for biochemical and cancer markers. Twelve patients underwent pathological examination before surgery. All patients were followed up by telephone or clinical visit. Postoperative liver function improvement, postoperative complications, stent patency time, and survival time were compared between the two groups. Prognostic risk factors were evaluated.

RESULTS

Technical success was achieved in all patients in both groups. Postoperative liver function improved significantly in all patients (total bilirubin, direct bilirubin, alanine aminotransferase, and aspartate aminotransferase decreased significantly in all patients, the P values were less than 0.05). There was no significant difference in preoperative or postoperative indexes between the two groups for changes in total bilirubin (P = 0.147), direct bilirubin (P = 0.448), alanine aminotransferase (P = 0.120), and aspartate aminotransferase (P = 0.387) between the two groups. The median stent patency time of the combined group was 9.0 ± 1.4 mo [95% confidence interval (CI): 6.3-11.8 mo], which was significantly longer than the that of the control group (6.0 ± 0.3 mo, 95%CI: 5.5-6.5 mo, P = 0.000). The median survival time of the combined group was 11.0 ± 1.4 mo (95%CI: 8.2-13.7 mo), which was significantly longer than that of the control group (7.0 ± 0.3 mo, 95%CI: 6.4-7.6 mo, P = 0.000). Location of obstruction and number of stents were independent risk factors affecting prognosis.

CONCLUSION

Biliary stent combined with ¹²⁵I seed strand implantation is safe and effective in malignant obstructive jaundice and improves stent patency time and median survival time.

A novel combination of percutaneous stenting with iodine-125 seed implantation and chemotherapy for the treatment of pancreatic head cancer with obstructive jaundice

PURPOSE

Insertion of radioactive strips through the biliary stent has been reported to offer longer survival and patency than an uncovered conventional self-expanding metal stent in patients with unresectable malignant biliary obstruction. The aim of this study was to investigate the safety and effectiveness of intraluminal brachytherapy combined with ¹²⁵I seed implantation and transarterial infusion chemotherapy for the treatment of pancreatic head cancer with obstructive jaundice.

METHOD

From October 2012 to January 2018, 21 consecutive patients diagnosed with biliary obstruction caused by locally advanced, nonmetastatic pancreatic cancer with cytologically or histologically confirmed by biopsy were enrolled and receive treatment with intraluminal brachytherapy using ¹²⁵I seed strand and CT-guided percutaneous radioactive seed implantation therapy. The procedure-related and radiation complications were assessed. The outcomes were measured in terms of stent patency, patient survival, complications related to the procedure.

RESULT

One of the 22 patients (4.5%, 1/22) with pancreatic head cancer failed to perform the above procedure because the guidewire was unable to pass through the obstruction segment. The remaining 21 patients (95.5%, 21/22) with pancreatic head cancer with obstructive jaundice were successfully placed with biliary stents and radioactive strips through drainage tubes. The median number of ¹²⁵I seeds loaded was 15, ranging from 12 to 17. After the chemotherapy with gemcitabine and cisplatin, no adverse reaction of Grade Ⅲ ∼ Ⅳ occurred in all cases. Median stent patency was 12.50 months (95% CI: 10.26, 14.74). By May 2019, all 21 patients had died, with overall survival of 5.2-23.3 months, with a median survival of 13.20 months (95% CI: 10.96, 15.44).

CONCLUSION

Percutaneous ¹²⁵I seed implantation combined with insertion of radioactive strips through the biliary stent has the characteristics of less trauma, fewer complications, simple operation, and so on. These procedures bring remission of obstructive jaundice combined with the increased survival for the treatment of obstructive jaundice caused by unresectable pancreatic head cancer if follow-up chemotherapy is carried out. The long-term efficacy of this treatment combination needs to be confirmed by further multicenter, large sample size prospective randomized controlled studies.

Feasibility and efficacy evaluation of metallic biliary stents eluting gemcitabine and cisplatin for extrahepatic cholangiocarcinoma

BACKGROUND

Effective endoscopic management is fundamental for the treatment of extrahepatic cholangiocarcinoma (ECC). However, current biliary stents that are widely used in clinical practice showed no antitumor effect. Drug-eluting stents (DESs) may achieve a combination of local chemotherapy and biliary drainage to prolong stent patency and improve prognosis.

AIM

To develop novel DESs coated with gemcitabine (GEM) and cisplatin (CIS)-coloaded nanofilms that can maintain the continuous and long-term release of antitumor agents in the bile duct to inhibit tumor growth and reduce systemic toxicity.

METHODS

Stents coated with different drug-eluting components were prepared by the mixed electrospinning method, with poly-L-lactide-caprolactone (PLCL) as the drug-loaded nanofiber membrane and GEM and/or CIS as the antitumor agents. Four different DESs were manufactured with four drug-loading ratios (5%, 10%, 15%, and 20%), including bare-loaded (PLCL-0), single-drug-loaded (PLCL-GEM and PLCL-CIS), and dual-drug-loaded (PLCL-GC) stents. The drug release property, antitumor activity, and biocompatibility were evaluated in vitro and in vivo to confirm the feasibility and efficacy of this novel DES for ECC.

RESULTS

The in vitro drug release study showed the stable, continuous release of both GEM and CIS, which was sustained for over 30 d without an obvious initial burst, and a higher drug-loaded content induced a lower release rate. The drug-loading ratio of 10% was used for further experiments due to its ideal inhibitory efficiency and relatively low toxicity. All drug-loaded nanofilms effectively inhibited the growth of EGI-1 cells in vitro and the tumor xenografts of nude mice in vivo; in addition, the dual-loaded nanofilm (PLCL-GC) had a significantly better effect than the single-drug-loaded nanofilms (P < 0.05). No significant differences in the serological analysis (P > 0.05) or histopathological changes were observed between the single-loaded and drug-loaded nanofilms after stent placement in the normal porcine biliary tract.

CONCLUSION

This novel PLCL-GEM and CIS-eluting stent maintains continuous, stable drug release locally and inhibits tumor growth effectively in vitro and in vivo. It can also be used safely in normal porcine bile ducts. We anticipate that it might be considered an alternative strategy for the palliative therapy of ECC patients.

International consensus statements for endoscopic management of distal biliary stricture

Distal biliary strictures (DBS) are common and may be caused by both malignant and benign pathologies. While endoscopic procedures play a major role in their management, a comprehensive review of the subject is still lacking. Our consensus statements were formulated by a group of expert Asian pancreatico-biliary interventional endoscopists, following a proposal from the Digestive Endoscopy Society of Taiwan, the Thai Association for Gastrointestinal Endoscopy, and the Tokyo Conference of Asian Pancreato-biliary Interventional Endoscopy. Based on a literature review utilizing Medline, Cochrane library, and Embase databases, a total of 19 consensus statements on DBS were made on diagnosis, endoscopic drainage, benign biliary stricture, malignant biliary stricture, and management of recurrent biliary obstruction and other complications. Our consensus statements provide comprehensive guidance for the endoscopic management of DBS.

Influence of Polymer Composition on the Controlled Release of Docetaxel: A Comparison of Non-Degradable Polymer Films for Oesophageal Drug-Eluting Stents

Following the huge clinical success of drug-eluting vascular stents, there is a significant interest in the development of drug-eluting stents for other applications, such as the treatment of gastrointestinal (GI) cancers. Central to this process is understanding how particular drugs are released from stent coatings, which to a large extent is controlled by drug-polymer interactions. Therefore, in this study we investigated the release of docetaxel (DTX) from a selection of non-degradable polymer films. DTX-polymer films were prepared at various loadings (1, 5 and 10% w/w) using three commercially available polymers including poly(dimethylsiloxane) (PSi), poly (ethylene-co-vinyl acetate) (PEVA) and Chronosil polyurethane (PU). The formulations were characterised using different techniques such as photoacoustic Fourier-transform infrared (PA-FTIR) spectrophotometry, X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The effect of DTX on the mechanical properties of the films, in-vitro release, and degradation tests were also assessed. For all polymers and DTX loadings, the drug was found to disperse homogenously without crystallisation within the polymer matrix. While no specific interactions were observed between DTX and PSi or PEVA, hydrogen-bonding appeared to be present between DTX and PU, which resulted in a concentration-dependent decrease in the Young’s moduli of the films due to disruption of inter-polymeric molecular interactions. In addition, the DTX-PU interactions were found to modulate drug release, providing near-linear release over 30 days, which was accompanied by a significant reduction in degradation products. The results indicate that DTX-loaded PU films are excellent candidates for drug-eluting stents for the treatment of oesophageal cancer.

Local Delivery of Gemcitabine Inhibits Pancreatic and Cholangiocarcinoma Tumor Growth by Promoting Epidermal Growth Factor Receptor Degradation

Gemcitabine is clinically used to treat certain types of cancers, including pancreatic and biliary cancer. We investigated the signal transduction pathways underlying the local antitumor effects of gemcitabine-eluting membranes (GEMs) implanted in pancreatic/biliary tumor-bearing nude mice. Here, we report that GEMs increased the E3 ubiquitin ligase c-CBL protein level, leading to degradation of epidermal growth factor receptor (EGFR) in SCK and PANC-1 cells. GEMs decreased the RAS and PI3K protein levels, leading to a reduction in the protein levels of active forms of downstream signaling molecules, including PDK, AKT, and GSK3β. GEM reduced proliferation of cancer cells by upregulating cell cycle arrest proteins, particularly p53 and p21, and downregulating cyclin D1 and cyclin B. Moreover, GEMs reduced the levels of proangiogenic factors, including VEGF, VEGFR2, CD31, and HIF-1α, and inhibited tumor cell migration and invasion by inducing the expression of E-cadherin and reducing that of N-cadherin, snail, and vimentin. We demonstrated that local delivery of gemcitabine using GEM implants inhibited tumor cell growth by promoting c-CBL-mediated degradation of EGFR and inhibiting the proliferation, angiogenesis, and epithelial–mesenchymal transition of pancreatic/biliary tumors. Use of gemcitabine-eluting stents can improve stent patency by inhibiting the ingrowth of malignant biliary obstructions.

Safety Evaluation of Paclitaxel-Eluting Biliary Metal Stent with Sodium Caprate in Porcine Biliary Tract

Background/Aims

Metallic stents designed to relieve malignant biliary obstruction are susceptible to occlusive tumor ingrowth or overgrowth. In a previous report, we described metallic stents covered with paclitaxel-incorporated membrane (MSCPM-I, II) to prevent occlusion from tumor ingrowth via antitumor effect. This new generation paclitaxeleluting biliary stent is further endowed with sodium caprate (MSCPM-III) for enhanced drug delivery. The purpose of this study is to examine the safety of its drug delivery system in the porcine biliary tract.

Methods

MSCPM-III (10% [wt/vol] paclitaxel) and covered metal stents (CMSs) were endoscopically inserted in porcine bile ducts in vivo. Histologic biliary changes, levels of paclitaxel released, and various serum analytes (albumin, alkaline phosphate, aspartate transaminase, alanine transaminase, total protein, total bilirubin, and direct bilirubin) were assessed.

Results

Based on the intensity of reactive inflammation and fibrosis, changes in porcine biliary epithelium secondary to implanted MSCPM-III were deemed acceptable (i.e., safe). Histologic features in the MSCPM-III and CMS groups did not differ significantly. In a related serum analysis, paclitaxel release from MSCPM-III stents was below the limit of detection for 28 days. Biochemical analyses were also similar for the two groups, and no evidence of hepatic or renal toxicity was found in animals receiving MSCPM-III stents.

Conclusions

In a prototypic porcine trial, this newly devised metal biliary stent incorporating both paclitaxel and sodium caprate appears to be safe in the porcine bile duct.

Percutaneous stenting and chemotherapy for unresectable pancreatic cancer: Comparison of irradiation stents vs conventional metal stents

OBJECTIVES

Percutaneous stenting is a palliative method to relieve obstructive jaundice caused by unresectable pancreatic carcinoma. In this study, we aimed to compare the safety and efficacy of irradiation stents and conventional metal stents.

METHODS

A total of 32 patients who received irradiation stents or conventional metal stents to treat obstructive jaundice caused by locally advanced pancreatic cancer were included in this retrospective study. Chemotherapy using gemcitabine was performed after jaundice subsided. Stent patency, technical success, survival, and complications were compared between groups.

RESULTS

Seventeen patients were enrolled in the irradiation stent group (ISG), and 15 patients were enrolled in the uncovered stent group (USG). Median and mean stent patency time were 9.8 months (95% CI, 7.682-11.981) and 9.506 months (95% CI, 8.0-11.012) in the ISG, respectively, vs 8.8 months (95% CI, 6.528-11.072) and 7.62 months (95% CI, 5.917-9.323) in the USG, respectively (P = 0.019). Median and mean overall survival were 10.4 months (95% CI, 8.383-12.417) and 9.953 months (95% CI, 8.408-11.498), respectively, in the ISG vs 9.7 months (95% CI, 7.901-11.499) and 8.14 months (95% CI, 6.44-9.84), respectively, in the USG (P = 0.027).

CONCLUSIONS

Irradiation stents extend stent patency and overall survival compared with conventional biliary stents for the treatment of pancreatic carcinoma complicated by obstructive jaundice. Irradiation stents combined with chemotherapy may be a better choice for the treatment of obstructive jaundice caused by unresectable pancreatic carcinoma.

Endoscopic Palliation for Biliary and Pancreatic Malignancies: Recent Advances

Malignancies of the pancreatobiliary system are usually unresectable at the time of diagnosis. As a consequence, a majority of these cases are candidates for palliative care. With advances in chemotherapeutic agents and multidisciplinary care, the survival rate in pancreatobiliary malignancies has improved. Therefore, there is a need to provide an effective and long-lasting palliative care for these patients. Endoscopic palliation is preferred to surgery as the former is associated with equal efficacy and reduced morbidity. The main role of endoscopic palliation in the vast majority of pancreatobiliary malignancies includes biliary and enteral stenting for malignant obstructive jaundice and gastric outlet obstruction, respectively. Recent advances in endoscopic palliation appear promising in imparting long-lasting relief of symptoms. Use of radiofrequency ablation and photodynamic therapy in malignant biliary obstruction has been shown to improve the survival rates as well as the patency of biliary stents. The emergence of endoscopic ultrasound (EUS) as a therapeutic tool has enhanced the capability of minimally invasive palliation in pancreatobiliary cancers. EUS is a valuable alternative to endoscopic retrograde cholangiopancreatography for the palliation of obstructive jaundice. More recently, EUS is emerging as an effective primary modality for biliary and gastric bypass.

Uncovered versus covered stent in management of large bowel obstruction due to colorectal malignancy: a systematic review and meta-analysis

PURPOSE

To compare outcomes of uncovered stent and covered stent in management of large bowel obstruction secondary to colorectal malignancy.

METHODS

We conducted a search of electronic databases identifying studies comparing outcomes of uncovered and covered stents in management of large bowel obstruction secondary to colorectal malignancy. The Cochrane risk-of-bias tool and the Newcastle-Ottawa scale were used to assess the included studies. Random or fixed effects modelling were applied as appropriate to calculate pooled outcome data.

RESULTS

One randomised controlled trial (RCT) and nine observational studies, enrolling 753 patients, were identified. Uncovered stent was associated with lower risks of complications (RR 0.57 95% CI 0.44-0.74, P < 0.0001), tumour overgrowth (RR 0.29 95% CI 0.09-0.93, P = 0.04), and stent migration (RR 0.29 95% CI 0.17-0.48, P < 0.00001); longer duration of patency (MD 18.47 95% CI 10.46-26.48, P < 0.00001); lower need for stent reinsertion (RR 0.38 95% CI 0.17-0.86, P = 0.02); and higher risk of tumour ingrowth (RR 4.53 95% CI 1.92-10.69, P = 0.0008). Rates of technical success (RR 1.02 95% CI 0.99-1.04, P = 0.21), clinical success (RR 1.03 95% CI 0.98-1.08, P = 0.32), perforation (RD 0.01 95% CI - 0.03-0.02, P = 0.65), bleeding (RD 0.00 95% CI - 0.03-0.03, P = 0.98), stool impaction (RR 0.56 95% CI 0.12-2.04, P = 0.38) and stent obstruction (RR 2.23 95% CI 0.94-5.34, P = 0.97) were similar.

CONCLUSIONS

Our results suggest that uncovered stents are superior as indicated by fewer complications, lower rates of stent migration, longer duration of patency and a reduced need for stent reinsertion. The best available evidence is mainly derived from non-randomised studies; there is a need for more RCTs.

Efficacy and safety evaluation of paclitaxel-loaded metal stents in patients with malignant biliary obstructions

Paclitaxel-eluting covered metal stents (PECMSs) and metallic stents covered with a paclitaxel-incorporated membrane (MSCPMs) have been developed to increase stent patency by preventing tumor ingrowth. However, few studies have compared their efficacy and safety compared with conventional covered metal stents (CMSs). This study aimed to compare differences in efficacy and safety between PECMS/MSCPM and CMS by meta-analysis. A search of PubMed and Embase was conducted for randomized controlled trials of PECMS/MSCPM and CMS in patients with malignant biliary obstructions published between January 1966 and August 2017. A meta-analysis was performed to compare clinical outcomes and complications between stent types. A total of 221 patients from three studies were included. There were no significant differences between PECMS/MSCPM and CMS in stent patency duration (P = 0.128) or survival time (P = 0.363). Risk did not differ between PECMS/MSCPM and CMS for stent malfunction (hazard ratio [HR]: 1.13, 95% confidence interval [CI]: 0.63-2.02, P = 0.677 for all stent malfunction; HR: 1.39, 95% CI: 0.68-2.85, P = 0.362 for stent occlusion caused by tumor ingrowth; HR: 0.80, 95% CI: 0.34-1.91, P = 0.617 for stent occlusion caused by distal stent migration or sludge impaction), or complications (HR: 1.54, 95% CI: 0.70-3.39, P = 0.280 for all complications; HR: 0.42, 95% CI: 0.14-1.30, P = 0.131 for pancreatitis). The exception was cholangitis-like symptoms, the risk for which was higher in PECMS/MSCPM compared with CMS (HR: 3.93, 95% CI: 1.08-14.29, P = 0.038). Although PECMS/MSCPM may be associated with higher risk of cholangitis-like symptoms, the overall results were similar between PECMS/MSCPM and CMS. Further studies are warranted in larger populations of patients.

Effects of Paclitaxel-conjugated N-Succinyl-Hydroxyethyl Chitosan Film for Proliferative Cholangitis in Rabbit Biliary Stricture Model

Background:

Paclitaxel (PTX) could inhibit the growth of fibroblasts, which occurs in proliferative cholangitis and leads to biliary stricture. However, its use has been limited due to poor bioavailability and local administration for short time. This study designed and synthesized a new PTX-conjugated chitosan film (N-succinyl-hydroxyethyl chitosan containing PTX [PTX-SHEC]) and evaluated its safety and efficiency using in vivo and in vitro experiments.

Methods:

The SHEC conjugated with PTX was confirmed by nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FT-IR) measurements. Drug releases in vitro and in vivo were determined using high-performance liquid chromatography. Cell viability in vitro was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. Rabbit biliary stricture model was constructed. All rabbits randomly divided into five groups (n = 8 in each group): the sham-operated rabbits were used as control (Group A), Groups B received laparotomies and suture, Group C received laparotomies and covered SHEC suture without the PTX coating, Group D received laparotomies and covered PTX-SHEC suture, and Group E received laparotomies and 1000 μmol/L PTX administration. Liver function tests and residual dosage of PTX from each group were measured by enzyme-linked immunosorbent assay. Histological data and α-smooth muscle actin (SMA) immunohistochemical staining of common bile duct were examined.

Results:

NMR and FT-IR indicated that PTX was successfully introduced, based on the appearance of signals at 7.41–7.99 ppm, 1.50 ppm, and 1.03 ppm, due to the presence of aromatic protons, methylene protons, and methyl protons of PTX, respectively. No bile leak was observed. The PTX-conjugated film could slowly release PTX for 4 weeks (8.89 ± 0.03 μg at day 30). The in vitro cell viability test revealed significantly different levels of toxicity between films with and without PTX (111.7 ± 4.0% vs. 68.1 ± 6.0%, P < 0.001), whereas no statistically significant difference was observed among the three sets of PTX-contained films (67.7 ± 5.4%, 67.2 ± 3.4%, and 59.1 ± 6.0%, P > 0.05). Histological examinations revealed that after 28 days of implantment, Groups D and E (but not Group C) had less granulation tissue and glandular hyperplasia in the site of biliary duct injury than Group B. The pattern was more obvious in Group D than Group E. Less α-SMA-positive cells were found in tissue from Groups D and E. Comparing with Group E, the liver function was improved significantly in Group D, including total bilirubin (2.69 ± 1.03 μmol/L vs. 0.81 ± 0.54 μmol/L, P = 0.014), alanine aminotransferase (87.13 ± 17.51 U/L vs. 42.12 ± 15.76 U/L, P = 0.012), and alkaline phosphatase (60.61 ± 12.31 U/L vs. 40.59 ± 8.78 U/L, P < 0.001).

Conclusions:

PTX-SHEC film effectively inhibites the myofibroblast proliferation and extracellular matrix over-deposition during the healing process of biliary reconstruction. This original film might offer a new way for reducing the occurrence of the benign biliary stricture.

Efficacy of a Multiplex Paclitaxel Emission Stent Using a Pluronic® Mixture Membrane versus a Covered Metal Stent in Malignant Biliary Obstruction: A Prospective Randomized Comparative Study

Background/Aims

A drug-eluting stent for unresectable malignant biliary obstruction was developed to increase stent patency by preventing tumor ingrowth. The safety and efficacy of a new generation of metallic stents covered with a paclitaxel-incorporated membrane using a Pluronic^® mixture (MSCPM-II) were compared prospectively with those of covered metal stents (CMSs) in patients with malignant biliary obstructions.

Methods

This study was initially designed as a prospective randomized trial but was closed early because of a high incidence of early occlusion. Therefore, the data were analyzed using the intent-to-treat method. A total of 72 patients with unresectable distal malignant biliary obstructions were prospectively enrolled.

Results

The two groups did not differ significantly in basic characteristics and mean follow-up period (MSCPM-II 194 days vs CMS 277 days, p=0.063). Stent occlusion occurred in 14 patients (35%) who received MSCPM-II and in seven patients (21.9%) who received CMSs. Stent patency and survival time did not significantly differ between the two groups (p=0.355 and p=0.570). The complications were mild and resolved by conservative management in both groups.

Conclusions

There were no significant differences in stent patency or patient survival in MSCPM-II and CMS patients with malignant biliary obstructions.

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.

Palliative Percutaneous Biliary Interventions in Malignant High Bile Duct Obstruction

The optimal palliative intervention for malignant biliary obstruction is internal drainage by placement of a metallic stent. For patients with hilar biliary obstruction or low bile duct obstruction in whom endoscopy is not feasible, a percutaneous transhepatic approach in interventional radiology is preferred. This article reviews the rationale for this approach, periprocedural management, and techniques to optimize stent patency.

Partially Covered Metal Stents May Not Prolong Stent Patency Compared to Uncovered Stents in Unresectable Malignant Distal Biliary Obstruction

BACKGROUND/AIMS

Controversy still exists regarding the benefits of covered self-expandable metal stents (SEMSs) compared to uncovered SEMSs. We aimed to compare the patency and stent-related adverse events of partially covered SEMSs (PC-SEMSs) and uncovered SEMSs in unresectable malignant distal biliary obstruction.

METHODS

A total of 134 patients who received a PC-SEMS or uncovered SEMS for palliation of unresectable malignant distal biliary obstruction were reviewed retrospectively. The main outcome measures were stent patency, stent-related adverse events, and overall survival.

RESULTS

The median stent patency was 118 days (range, 3 to 802 days) with PC-SEMSs and 105 days (range, 2 to 485 days) with uncovered SEMSs (p=0.718). The overall endoscopic revision rate due to stent dysfunction was 36.6% (26/71) with PC-SEMSs and 36.5% (23/63) with uncovered SEMSs (p=0.589). Tumor ingrowth was more frequent with uncovered SEMSs (4.2% vs 19.1%, p=0.013), but migration was more frequent with PC-SEMSs (11.2% vs 1.5%, p=0.04). The incidence of stent-related adverse events was 2.8% (2/71) with PC-SEMSs and 9.5% (6/63) with uncovered SEMSs (p=0.224). The median overall survival was 166 days with PC-SEMSs and 168 days with uncovered SEMSs (p=0.189).

CONCLUSIONS

Compared to uncovered SEMSs, PC-SEMSs did not prolong stent patency in unresectable malignant distal biliary obstruction. Stent migration was more frequent with PC-SEMSs. However, tumor ingrowth was less frequent with PC-SEMSs compared to uncovered SEMSs.

The effect of paclitaxel-eluting covered metal stents versus covered metal stents in a rabbit esophageal squamous carcinoma model

BACKGROUND

The use of self-expanding metallic stents (SEMSs) is the current treatment of choice for malignant gastrointestinal obstructions. However, these stents can promote only drainage and have no antitumor effect. Some studies have reported that drug-eluting SEMSs may have tumor inhibition potential. The aim of this study was to evaluate the efficiency and safety of paclitaxel-eluting SEMSs (PEMSs) in rabbit esophageal cancer models.

MATERIALS AND METHODS

A PEMS was covered with a paclitaxel-incorporated membrane, in which the concentration of paclitaxel was 10% (wt/vol). The rabbit models were created endoscopically. Then, a PEMS or SEMS was endoscopically inserted into the rabbit esophagus. Two weeks after stent placement, the rabbits were sacrificed, and we evaluated the tumor volume, area of the wall defect, area of the tumor under endoscopic ultrasound (EUS) before and after stent placement, status of the proximal esophageal obstruction, tumor metastasis food-intake and weight loss.

RESULTS

A total of 26 rabbits received stent insertion and survived until sacrifice, and migration occurred in 4 cases, 3 in SEMS group and 1 in PEMS group. For the remaining 22 rabbits, at the sacrificed time, the average tumor volume was 7.00±4.30 cm3 in the SEMS group and 0.94±1.51 cm3 in the PEMS group (P<0.05). The area of the esophageal wall defect was 0.70±0.63 cm2 in the SEMS group and 0.17±0.16 cm2 in the PEMS group (P<0.05). The tumor area under EUS was 4.40±1.47 cm2 in the SEMS group and 1.30±1.06 cm2 in the PEMS group (P<0.05). At the time of stent placement, tumor area under EUS was comparable in the two groups. Other indices did not significantly differ between the two groups.

CONCLUSIONS

SEMS and PEMS are both safe and effective to relieve dysphagia in rabbit esophageal cancer models. A PEMS can serve as an alternative tool for advanced esophageal cancer that may inhibit tumor growth by serving as a drug sustained-release platform. Clinical trials of the stent are warranted in the future.

In Vitro and In Vivo Assessment of Docetaxel Formulation Developed for Esophageal Stents

Esophageal cancer (EC) mostly affects the elderly population and is frequently diagnosed at an advanced stage. Self-expanding metal stents (SEMS) are the most popular mode of palliation, but they are associated with reocclusion caused by tumor growth. To overcome this problem, docetaxel (DTX)-loaded polyurethane formulations were prepared for stent application. The films were evaluated against the cancer cell lines, OE-19 and OE-21, and normal esophageal cell line Het-1A. The DTX and the formulations were evaluated in vitro for the cytotoxicity and in vivo in nude mice. It was found that DTX and the formulations have a weak activity against the EC cell lines and an even weaker activity against Het-1A cell line. Preliminary in vivo studies showed skin toxicity in nude mice necessitating modification of the formulation. Reevaluation in a mouse xenograft model resulted in toxicity at high dose formulations while the low dose formulation exhibited modest advantage over commercial IV formulation; however, there was no significant difference between the commercial IV and blank formulation. DTX combination with an anti-cancer agent having complementary mode of action and non-overlapping toxicity could yield better outcome in future.

A pilot study of intraluminal brachytherapy using 125I seed strand for locally advanced pancreatic ductal adenocarcinoma with obstructive jaundice

PURPOSE

To investigate the safety and feasibility of intraluminal brachytherapy using 125I seed strand for locally advanced pancreatic ductal adenocarcinoma with obstructive jaundice.

METHODS AND MATERIALS

From January 2010 to February 2015, 18 consecutive patients diagnosed with locally advanced, nonmetastatic, inoperable pancreatic ductal adenocarcinoma with obstructive jaundice were enrolled and underwent intraluminal brachytherapy using 125I seed strand. Dose calculation was performed using a software. The procedure-related and radiation complications were assessed. Obstruction-free survival and overall survival were calculated using the Kaplan-Meier method.

RESULTS

The technique successful rate of 125I seed strand implantation was 100%. Successful bile drainage was achieved in all patients. The estimated mean accumulating dose (R = 5 mm, z = 0, 240 days) was 167.2 Gy, from 164.19 to 170.05 Gy. Two patients had adverse event of Grade 3, one of Grade 4. Stent dysfunction occurred in 1/18 (5.6%) patients. The mean and median obstruction-free survival time were 10.61 months (95% confidence interval [CI]: 7.04, 14.18) and 7.26 months (95% CI: 2.14, 12.38). The mean and median overall survival time were 11.91 months (95% CI: 7.39, 16.43) and 7.26 months (95% CI: 2.14, 12.38).

CONCLUSIONS

Intraluminal brachytherapy using 125I seed strand may be consider as a safe treatment option for the therapy of locally advanced pancreatic duct adenocarcinoma complicated by obstructive jaundice with acceptable complication rates.

Effect of a paclitaxel-eluting metallic stent on rabbit esophagus

The use of self-expanding metallic stents (SEMS) is the current treatment of choice for malignant gastrointestinal obstructions. A paclitaxel-eluting metallic SEMS (PEMS) may have an antitumor effect on esophageal tissue. PEMS with 10% paclitaxel or conventional SEMS were inserted into the lower esophagus of rabbits. Following the insertion of the stents for 1, 2, 4 and 6 weeks, the rabbits were sacrificed and the status of the stent insertion was examined, as well as any macroscopic or microscopic mucosal changes in the esophageal tissue. All the rabbits survived until death without any complications. No migration following stent insertion occurred. The number of cases with proximal obstruction increased in a time-dependent manner, and no significant difference was observed between the two groups. Gross histological examination showed similar tissue reaction to the stents at 1, 2 and 4 weeks, and inflammatory cell infiltrating was higher in the SEMS group at 1 and 2 weeks. However, inflammatory cell infiltration was markedly higher in the PEMS group at 4 and 6 weeks. Food-intake and weight were similar in the two groups. The results of the present study demonstrated that PEMS may serve as a safe alternative treatment strategy for esophageal obstruction. Furthermore, PEMS may inhibit the tumor growth of the esophageal wall through inflammatory infiltration and targeted drug delivery. A tumor model will be required in the future for evaluating the prognosis of patients with advanced esophageal carcinoma.

The endoscopist's role in the diagnosis and management of pancreatic cancer

Pancreatic cancer remains one of the most lethal malignancies with little improvement in survival over the past several decades in spite of advances in imaging, risk factor identification, surgical technique and chemotherapy. This disappointing outcome is mainly due to failures to make an early diagnosis. In fact, the majority of the patients present with inoperable advanced stages of the disease. Though some of the new tumor markers are promising, we are still in search of the one that has a high sensitivity and accuracy, yet is inexpensive and easy to obtain. The paradigm of management has shifted from up-front surgery followed by adjuvant chemotherapy to neoadjuvant chemoradiation followed by surgery, especially for borderline resectable cancers and even for some resectable cancers. In this article, we will critically assess the limitations of tumor markers and review the advancements in endoscopic techniques in the management of pancreatic cancer.

Basic Knowledge about Metal Stent Development

Biliary self-expandable metal stents (SEMS), a group of non-vascular stents, have been used in the palliative management of biliary obstruction around the world. However, there are still unmet needs in the clinical application of biliary SEMS. Comprehensive understanding of the SEMS is required to resolve the drawbacks and difficulties of metal stent development. The basic structure of SEMS, including the materials and knitting methods of metal wires, covering materials, and radiopaque markers, are discussed in this review. What we know about the physical and mechanical properties of the SEMS is very important. With an understanding of the basic knowledge of metal stents, hurdles such as stent occlusion, migration, and kinking can be overcome to develop more ideal SEMS.

Covered Stents versus Uncovered Stents for Unresectable Malignant Biliary Strictures: A Meta-Analysis

Aim. To summarize the covered or uncovered SEMS for treatment of unresectable malignant distal biliary obstruction, comparing the stent patency, patient survival, and incidence of adverse events between the two SEMSs. Methods. The meta-analysis search was performed independently by two of the authors, using MEDLINE, EMBASE, OVID, and Cochrane databases on all studies between 2010 and 2015. Pooled effect was calculated using either the fixed or the random effects model. Results. Statistics shows that there is no difference between SEMSs in the hazard ratio for patient survival (HR 1.04; 95% CI, 0.92–1.17; P = 0.55) and stent patency (HR 0.87, 95% CI: 0.58 to 1.30, P = 0.5). However, incidence of adverse events (OR: 0.74, 95% CI: 0.57 to 0.97, P = 0.03) showed significant different results in the covered SEMS, with dysfunctions events (OR: 0.75, 95% CI: 0.56 to 1.00, P = 0.05) playing a more important role than complications (OR: 0.87, 95% CI: 0.58 to 1.30, P = 0.50). Conclusions. Covered SEMS group had lower incidence of adverse events. There is no significant difference in dysfunctions, but covered SEMS trends to be better, with no difference in stent patency, patient survival, and complications.

Development of Biliary and Enteral Stents by the Korean Gastrointestinal Endoscopists

Stenting in the gastrointestinal tract is a common procedure used for palliation of obstruction in the enteral and biliary tract. Today, stenting of malignant and benign strictures is performed at almost every major tertiary hospital in Korea. Moreover, Korea has become a major global supplier of cutting edge technology in the field of self-expanding metal stents. However, the history of stenting in Korea is relatively short and was far behind that of other nations such as Japan and Germany. The authors are humbled and gratified to have been able to observe the development and application of these stents in Korea, first hand. In this article, the authors review the overall history of stenting with a specific focus on the development of stenting in Korea. The development of esophageal, gastroduodenal, biliary, and colonic stents in Korea are reviewed in this article from a chronological and historical point of view, and a personal account of some of the significant moments of stent development in Korea are described.

Current Status of Biliary Metal Stents

Many advances have been achieved in biliary stenting over the past 30 years. Endoscopic stent placement has become the primary management therapy to relieve obstruction in patients with benign or malignant biliary tract diseases. Compared with plastic stents, a self-expandable metallic stent (SEMS) has been used for management in patients with malignant strictures because of a larger lumen and longer stent patency. Recently, SEMS has been used for various benign biliary strictures and leaks. In this article, we briefly review the characteristics of SEMS as well as complications of stent placement. We review the current guidelines for managing malignant and benign biliary obstructions. Recent developments in biliary stenting are also discussed.

Malignant Biliary Obstruction: Evidence for Best Practice

What should be done next? Is the stricture benign? Is it resectable? Should I place a stent? Which one? These are some of the questions one ponders when dealing with biliary strictures. In resectable cases, ongoing questions remain as to whether the biliary tree should be drained prior to surgery. In palliative cases, the relief of obstruction remains the main goal. Options for palliative therapy include surgical bypass, percutaneous drainage, and stenting or endoscopic stenting (transpapillary or via an endoscopic ultrasound approach). This review gathers scientific foundations behind these interventions. For operable cases, preoperative biliary drainage should not be performed unless there is evidence of cholangitis, there is delay in surgical intervention, or intense jaundice is present. For inoperable cases, transpapillary stenting after sphincterotomy is preferable over percutaneous drainage. The use of plastic stents (PS) has no benefit over Self-Expandable Metallic Stents (SEMS). In case transpapillary drainage is not possible, Endoscopic Ultrasonography- (EUS-) guided drainage is still an option over percutaneous means. There is no significant difference between the types of SEMS and its indication should be individualized.

Effect of polymer microstructure on the docetaxel release and stability of polyurethane formulation

PurSil®AL20 (PUS), a copolymer of 4,4'-dicyclohexylmethane diisocyanate (HMDI), 1,4-butane diol (BD), poly-tetramethylene oxide (PTMO) and poly-dimethyl siloxane (PDMS) was investigated for stability as a vehicle for Docetaxel (DTX) delivery through oesophageal drug eluting stent (DES). On exposure to stability test conditions, it was found that DTX release rate declined at 4 and 40 °C. In order to divulge reasons underlying this, changes in DTX solid state as well as PUS microstructure were followed. It was found that re-crystallization of DTX in PDMS rich regions was reducing the drug release at both 4 °C and 40 °C samples. So far microstructural features have not been correlated with stability and drug release, and in this study we found that at 40 °C increase in microstructural domain sizes and the inter-domain distances (from ∼85 Å to 129 Å) were responsible for hindering the DTX release in addition to DTX re-crystallization.

Engineering Stent Based Delivery System for Esophageal Cancer Using Docetaxel

Esophageal cancer patients are often diagnosed as "advanced" cases. These patients are subjected to palliative stenting using self-expanding metallic stents (SEMS) to maintain oral alimentation. Unfortunately, SEMS get reoccluded due to tumor growth, in and over the stent struts. To investigate potential solutions to this problem, docetaxel (DTX) delivery films were prepared using PurSil AL 20 (PUS), which can be used as a covering material for the SEMS. Drug-polymer miscibility and interactions were studied. Bilayer films were prepared by adhering the blank film to the DTX loaded film in order to maintain the unidirectional delivery to the esophagus. In vitro release and the local DTX delivery were studied using in vitro permeation experiments. It was found that DTX and PUS were physically and chemically compatible. The bilayer films exhibited sustained release (>30 days) and minimal DTX permeation through esophageal tissues in vitro. The rate-determining step for the DTX delivery was calculated. It was found that >0.9 fraction of rate control lies with the esophageal tissues, suggesting that DTX delivery can be sustained for longer periods compared to the in vitro release observed. Thus, the bilayer films can be developed as a localized sustained delivery system in combination with the stent.

An Update to Hepatobiliary Stents

Endoscopic stent placement is a common primary management therapy for benign and malignant biliary strictures. However, continuous use of stents is limited by occlusion and migration. Stent technology has evolved significantly over the past two decades to reduce these problems. The purpose of this article is to review current guidelines in managing malignant and benign biliary obstructions, current endoscopic techniques for stent placement, and emerging stent technology. What began as a simple plastic stent technology has evolved significantly to include uncovered, partially covered, and fully covered self-expanding metal stents (SEMS) as well as magnetic, bioabsorbable, drug-eluting, and antireflux stents.(1).

Novel biliary self-expanding metal stents: indications and applications

Endoscopic insertion of a self-expanding metal stent (SEMS) through a malignant common bile duct stricture is the first line of palliation for malignant jaundice. Patency of these stents remains a major concern. SEMS dysfunction can result from tumor ingrowth, overgrowth and/or clogging. Initial SEMS modifications involved covering the central part of the stent in order to reduce ingrowth and ultimately increase patency. Fully covered stents became available shortly after reports of their use in human patients. The potential removability and radial strength of SEMS have led to evaluation of their use in new indications including benign biliary strictures, post sphincterotomy bleeding and perforation. Other aspects of development include the addition of features such as anti-reflux valves, drug elution and spontaneous biodegradability. These aspects and their clinical implications are reviewed and discussed.

Selenium doped Ni–Ti layered double hydroxide (Ni–Ti LDH) films with selective inhibition effect to cancer cells and bacteria

Selenium doped LDH films effectively inhibit the growth of cancer cells and bacteria with little adverse effect on normal cells. The selectivity stems from the synergistic effect of the doped selenium and hydroxyl radicals produced by the LDH films.

Use of stents in treatment of malignant biliary obstruction

Stents are now recognized as the first choice of palliative therapy for malignant biliary obstruction. Since stents can effectively relieve obstruction, reduce jaundice, and improve the quality of life, their usage in inoperable biliary tract cancer patients has broad prospects. This paper reviews the use of stents in the treatment of malignant biliary obstruction with regards to stent type, selection, placement and the combination of stenting with other means of treatment.

Electrospun polyurethane/Eudragit ® L100-55 composite mats for the pH dependent release of paclitaxel on duodenal stent cover application

A nanofiber composite mat of PU and Eudragit(®) L100-55 was created using electrospinning process. The pH dependent release of paclitaxel was successfully done with the use of PU/EL100-55 nanocomposite mats as the controlling platform. The morphology of the nanofiber composites was surveyed using FESEM and ratios of the polymers affects the diameter of the nanofiber. Characterization of the nanofiber composite mat was done using FTIR, DSC-TGA method. The release rate of paclitaxel was determined and analyzed by in vitro drug release method. In order to mimic the condition of a human duodenum, the fibers were submersed on PBS of different pH levels (4.0, 6.0,) respectively, and then analyzed using high performance liquid chromatography (HPLC). Composite mats submersed in PBS with pH 4.0 showed lesser release profile compared to mats submersed in PBS with pH of 6.0. The composite mat has adequate mechanical properties and in vitro cell biocompatibility indicating that the material can be used for drug eluting stent cover application.

Endoscopic treatment options for cholangiocarcinomas

Cholangiocellular carcinoma (CCC) is a very aggressive tumor, which remains highly resistant to current chemoradiation therapies. Death is usually caused by the tumor burden. However, biliary obstruction, which leads to cholangitis and liver failure, is also a cause of death. Therefore, relief of biliary obstruction is one of the key palliative treatment options for patients with hilar or distal CCC. Radiologic or endoscopic insertions of stents (plastic or self-expanding metal) are definite biliary drainage options. Whereas stents alone can help achieve relief of bile duct obstruction, endoscopic ablative interventions with photodynamic therapy or radiofrequency ablation are also useful in destroying intraluminal tumor. Destroying the tumor leads to an increase in the luminal diameter of the obstructed bile duct, allowing for placement of more or larger diameter stents, and thus improving bile flow. Besides decreasing morbidity associated with obstruction, ablative therapies such as photodynamic therapy have also been associated with improved survival in a sub-group of patients with CCC and should therefore be incorporated into the treatment algorithm of any center treating patients with CCC.

Biliary stenting for cholangiocarcinoma: An update

Cholangiocarcinoma (bile duct cancer) is the most common malignant tumor of the biliary tree. This devastating malignancy presents late, and is notoriously difficult to diagnose, thus resulting a high mortality. The majority of cholangiocarcinoma patients present with an unresectable disease, and survive less than 12 mo following diagnosis. Biliary stent placement is an effective palliative therapy for malignant biliary obstruction, which can significantly improve the quality of life, and extend the survival time of patients. Different biliary stent placement methods would closely affect the prognosis of patients. The purpose of this article is to review the treatment efficacy, insertion paths and types of biliary stents. This paper also covers emerging biliary stents including drug stents, and biliary stent combination local therapy.

Histological Changes in the Bile Duct after Long-Term Placement of a Fully Covered Self-Expandable Metal Stent within a Common Bile Duct: A Canine Study

Background/Aims

To date, it has been difficult to determine the optimal stenting duration of a fully covered self-expandable metal stent (FCSEMS) in a benign biliary stricture. The purpose of this study was to identify the histopathological changes in a bile duct resulting from long-term placement of a FCSEMS.

Methods

An FCSEMS was inserted into the common bile duct of 12 canines, and the animals were divided into four groups. Posteuthanasia, necropsy was performed to examine the histopathological changes in the bile ducts after 1, 3, 6, and 9 months.

Results

The results of necropsy showed that the covered membranes of the FCSEMSs were intact and easily removed from the bile ducts in 11 of the canines. Severe epithelial hyperplasia of the stented bile duct and epithelial ingrowth into the stent occurred in one animal (from the 3-month group). On histopathological examination, mild inflammatory changes were observed in the stented bile ducts, and there was no significant difference between the four groups. Among the 12 animals, five had de novo stricture.

Conclusions

An FCSEMS can be inserted into the bile duct without severe histopathological changes up until 9 months. However, a de novo stricture and severe epithelial hyperplasia relating to the stent insertion might occur.