A study of carboplatin-coated tube for the unresectable cholangiocarcinoma

Biliary stents for active materials and surface modification: Recent advances and future perspectives

Demand for biliary stents has expanded with the increasing incidence of biliary disease. The implantation of plastic or self-expandable metal stents can be an effective treatment for biliary strictures. However, these stents are nondegradable and prone to restenosis. Surgical removal or replacement of the nondegradable stents is necessary in cases of disease resolution or restenosis. To overcome these shortcomings, improvements were made to the materials and surfaces used for the stents. First, this paper reviews the advantages and limitations of nondegradable stents. Second, emphasis is placed on biodegradable polymer and biodegradable metal stents, along with functional coatings. This also encompasses tissue engineering & 3D-printed stents were highlighted. Finally, the future perspectives of biliary stents, including pro-epithelialization coatings, multifunctional coated stents, biodegradable shape memory stents, and 4D bioprinting, were discussed.

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.

Antitumor effect of the paclitaxel-eluting membrane in a mouse model

Local treatment of primary bile duct cancer, which grows locally at the primary lesion and seldom metastasizes to distant sites, is challenging. The present study evaluated the antitumor effect, systemic toxicity, biodistribution and survival benefit of the paclitaxel-eluting polyurethane membrane in a tumor model. Membranes containing various amounts of paclitaxel (0, 100, 300, 600 and 1,200 µg/disc) were inserted beneath the tumor mass in mouse models. Tumor size and body weight of the tumor models were monitored for 26 days after insertion of the membrane. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay was performed in the tumor tissues. High-performance liquid chromatography was performed for evaluation of paclitaxel concentration in peripheral tissues. Tumor volumes on day 26 of membrane treatment were decreased in a dose-dependent manner. No significant difference in body weight was observed in the groups. A greater number of apoptotic cells were counted per high power field in tumor tissues following an increase of paclitaxel concentration. In the 1,200 µg-group, concentrations of paclitaxel were significantly higher in tumors compared with those of other tissues and serum. The paclitaxel-eluting membrane demonstrated a significant and dose-dependent antitumor activity, and did not exert systemic toxicity in the tumor model.

Preclinical evaluation of sorafenib-eluting stent for suppression of human cholangiocarcinoma cells

Background

Cholangiocarcinoma is a malignant tumor arising from the epithelium of the bile ducts. In this study, we prepared sorafenib-loaded biliary stents for potential application as drug-delivery systems for localized treatment of extrahepatic cholangiocarcinoma.

Methods

A sorafenib-coated metal stent was prepared using an electrospray system with the aid of poly(ɛ-caprolactone) (PCL), and then its anticancer activity was investigated using human cholangiocellular carcinoma (HuCC)-T1 cells in vitro and a mouse tumor xenograft model in vivo. Anticancer activity of sorafenib against HuCC-T1 cells was evaluated by the proliferation test, matrix metalloproteinase (MMP) activity, cancer cell invasion, and angiogenesis assay in vitro and in vivo.

Results

The drug-release study showed that the increased drug content on the PCL film induced a faster drug-release rate. The growth of cancer cells on the sorafenib-loaded PCL film surfaces decreased in a dose-dependent manner. MMP-2 expression of HuCC-T1 cells gradually decreased according to sorafenib concentration. Furthermore, cancer cell invasion and tube formation of human umbilical vein endothelial cells significantly decreased at sorafenib concentrations higher than 10 mM. In the mouse tumor xenograft model with HuCC-T1 cells, sorafenib-eluting PCL films significantly inhibited the growth of tumor mass and induced apoptosis of tumor cells. Various molecular signals, such as B-cell lymphoma (Bcl)-2, Bcl-2-associated death promoter, Bcl-x, caspase-3, cleaved caspase-3, Fas, signal transducer and activator of transcription 5, extracellular signal-regulated kinases, MMP-9 and pan-janus kinase/stress-activated protein kinase 1, indicated that apoptosis, inhibition of growth and invasion was cleared on sorafenib-eluting PCL films.

Conclusion

These sorafenib-loaded PCL films are effective in inhibiting angiogenesis, proliferation and invasion of cancer cells. We suggest that sorafenib-loaded PCL film is a promising candidate for the local treatment of cholangiocarcinoma.

Safety evaluation of self-expanding metallic biliary stents eluting gemcitabine in a porcine model

BACKGROUND AND AIM

Palliative biliary decompression by metal stent is the treatment of choice for unresectable malignant biliary obstruction; however, conventional stents provide only mechanical palliation and exert no anti-tumor effects. Gemcitabine (GEM) has been reported to be more effective in unresectable pancreatic cancer and biliary cancer compared with other chemotherapeutic drugs. We evaluated the safety of a GEM-eluting stent by analyzing histologic responses of the porcine bile duct.

METHODS

Stents containing GEM (0%, 10%, 15%, and 20% [w/v]) were surgically inserted into bile ducts of pigs (each group, n = 2). The animals were euthanized after 4 weeks, and the stented bile duct segment underwent gross and microscopic examination. Laboratory assay was performed for aspartate transaminase (AST), alanine transaminase (ALT), total bilirubin, and gamma-glutamyl transferase (γ-GTP).

RESULTS

Moderate to severe inflammation was observed in the bile ducts in contact with stents containing 15 and 20% GEM, compared with no inflammation with 0% GEM and mild inflammation with 10% GEM. Fibrous reactions observed in the submucosal layer did not differ among groups. Transmural necrosis and perforations were not observed in any animal. No abnormal laboratory test findings were directly caused by GEM.

CONCLUSION

Our newly developed GEM eluting stents can be used safely in normal bile ducts. Our results indicated that 10% GEM produced mild histologic changes in the stented segment and adjacent tissue; this concentration may be appropriate for clinical application.

Drug-eluting stent in malignant biliary obstruction

INTRODUCTION

In unresectable malignant bile duct obstruction, endoscopic stent insertion is the treatment of choice. However, the current stent allows only mechanical palliation of the obstruction, and has no anti-tumor effect. Currently, in the vascular field, the drug-eluting stent (DES) is very highly favored.

MATERIAL AND METHODS

The requirements for a DES in a non-vascular tract, such as the bile duct, are far different from those of a DES to be used in the vascular tract. The non-vascular DES must suppress tumor proliferation as well as mucosal hyperplasia. For example, the non-vascular stent might be covered with a membrane that gradually releases a chemo-agent. We do not have much experience with DES in the bile duct. Nonetheless, we are continuously testing many anti-tumor agents in animal and human studies.

CONCLUSION

We expect and hope DES will work effectively for tumor cells in diverse ways and, more importantly, will prolong stent patency and the patients' survival periods. But considerable investigation and a clinical study of DES will be required to achieve these goals.

Cholangiocarcinoma: A compact review of the literature

Cholangiocarcinoma (CC) is a devastating cancer arising from biliary epithelia. Unfortunately, the incidence of this disease is increasing in Western countries. These tumors progress insidiously, and liver failure, biliary sepsis, malnutrition and cancer cachexia are general modes of death associated with this disease. To date, no established therapy for advanced disease has been established or validated. However, our knowledge in tumor biology is increasing dramatically and new drugs are under investigation for treatment of this notorious tumor. In clinical practice, there are better diagnostic tools in use to facilitate an earlier diagnosis of CC, at least in those patients with known risk factors. CC is resectable for cure in only a small percentage of patients. Preoperative staging for vascular and biliary extension of CC is very important in this tumor. Laparoscopy and recently endosonography seem to protect against unnecessary laparotomies in these patients. During the last 15 years, aggressive surgical approaches, including combined liver resections and vascular reconstructive surgical expertise, have improved survival in patients with CC. Surgery is contraindicated in CC cases having primary sclerosing cholangitis (PSC). Although CC was previously considered a contraindication to liver transplantation, new cautious protocols, including neo-adjuvant chemoradiation therapies and staging procedures before the transplantation, have made it possible to achieve long-term survival after liver transplantation in this disease. New ablative therapies with photodynamic therapy, intraductal high-intensity ultrasonography and chemotherapy-impregnated plastic biliary endoprosthesis are important steps in the palliative management of extra-hepatic CCs. Radiofrequency and chemo-embolization methods are also applicable for intra-hepatic CCs as palliative modes of treatment. We need more prospective randomized controlled trials to evaluate the role of the new emerging therapies for CC patients.

Endoscopic management of biliary malignancies

The current status of endoscopic diagnosis and treatment of biliary malignancies is discussed. Three ways are now available to approach the bile duct endoscopically. Endoscopic diagnostic modalities are quite useful for the assessment of local changes because of their high spatial resolution and ability in tissue and bile acquisition for histologic, cytologic, and molecular biologic evaluations. Endoscopic biliary drainage is less invasive and beneficial for patients with obstructive jaundice compared with surgical or percutaneous transhepatic drainage. Continuous evolution should expand its indications.

Diagnosis and initial management of cholangiocarcinoma with obstructive jaundice

Cholangiocarcinoma is the second most common primary hepatic cancer. Despite advances in diagnostic techniques during the past decade, cholangiocarcinoma is usually encountered at an advanced stage. In this review, we describe the classification, diagnosis, and initial management of cholangiocarcinoma with obstructive jaundice.

Multidisciplinary approach to benign biliary strictures

The various approaches used for the management of patients with benign biliary strictures are justified by the diverse nature, clinical presentation, and severity of these strictures. Benign biliary strictures are most commonly postoperative, a consequence of injury during laparoscopic cholecystectomy or fibrosis after biliary duct-to-duct or bilioenteric anastomoses (ie, liver transplantation). Less frequently, benign strictures are due to chronic pancreatitis or other nonmalignant diseases, including external compression, parasites, stone perforation, and infections. Because of their peculiar pathogenesis, localization, and short extension into the bile duct, the majority of these strictures can be approached by operative treatments such as surgical bypass and endoscopic--or radiological--dilation. In contrast, primary sclerosing cholangitis (PSC) is a systemic disease with immune-mediated inflammation and subsequent fibrosis of the bile ducts with the development of multiple strictures due to an "intrinsic" liver disease; thus, medical therapy and pharmacologic research are mainly focused on the treatment of PSC rather than other benign biliary strictures. However, none of the previously mentioned benign strictures has a univocal and sole treatment. Any attempt to identify a standard treatment for all the strictures is questionable, inconclusive, and most likely useless due to the diversity of patients and diseases. Gastroenterologists, radiologists, and surgeons work in tight collaboration, not in competition, to individualize the patients' treatment. The morphology and extension of the stricture, its location, the theoretical pathogenesis (eg, intrinsic strictures, strictures due to inflammation and fibrosis after bile leak, ischemic lesions), the patients' specific characteristics (comorbidity and history of prior surgery, including enterobiliary anastomoses and gastric resection), and preferences should indicate the treatment that may offer the patient major benefits with a lower complication rate. Unfortunately, in most of the cases, choosing between different treatments is more likely based on local availability than their actual effectiveness and indication.

Local delivery system of immune modulating drug for unresectable adenocarcinoma: in vitro experimental study and in vivo animal study

The purpose of the study was to evaluate the efficacy and safety of a developed drug delivery system containing OK-432 through in vitro and animal study. An OK-432-impregnated polycarbonate/polyurethane stent membrane was used to develop a drug delivery system (DDS) enabling the locoregional release of OK-432. Polyethyleneglycol was used as a detergent and porosity generator. The stability of OK-432 in solvent, releasing kinetics of drug, and cytotoxicity of the DDS were evaluated. OK-432-impregnated DDS was implanted in mice in which a human adenocarcinoma cell line was injected and grown in their back. Flow cytometry and enzyme-linked immunosorbent assay were used for quantifying the amount of drug. OK-432 exposed to phosphate-buffered saline and OK-432 exposed to N,N-dimethylacetamide showed similar results on dot graphs and histograms. However, OK-432 exposed to tetrahydrofurane showed different dot graphs and histograms, which means that the antigenicity of the drug was changed. The release rate of OK-432 was maintained at a constant level for 6 weeks. The local delivery of OK-432 was found to have an antitumor effect on a human adenocarcinoma cell line in an animal study, but no effect on this cell line in in vitro cell culture. Histologic examination showed minimal inflammatory reaction in surrounding tissue. Our study shows that local treatment using this OK-432 release system is safe and effective in reducing adenocarcinoma in a mouse model.

Endoscopic palliation of pancreaticobiliary malignancies

The palliation of pancreaticobiliary malignancies has changed over the last two decades. With the development of biliary stents, minimally invasive procedures have replaced surgical techniques. Endoscopically placed stents remain the mainstay for the palliative treatment of malignant biliary obstruction from unresectable pancreaticobiliary tumors. Further improvements in stent designs and advances in other endoscopic technologies are expected, and these should expand the role of minimally invasive palliation. This article reviews the current and anticipated roles of endoscopic techniques in the palliation of pancreaticobiliary malignancies.

Palliative therapy for pancreatic/biliary cancer

Palliative treatment for unresectable periampullary cancer is directed at three major symptoms: obstructive jaundice, duodenal obstruction, and cancer-related pain. In most cases, the pattern of symptoms at the time of diagnosis in the context of the patient's medical condition and projected survival influence the decision to perform an operative versus a non operative palliative procedure. Despite improvements in preoperative imaging and laparoscopic staging of patients with periampullary cancer and hilar cholangiocarcinoma, surgical exploration is the only modality that can definitively rule out resectability and the potential for curative resection in some patients with nonmetastatic cancer. Furthermore, only surgical management achieves successful palliation of obstructive symptoms and cancer-related pain as a single procedure during exploration. To take advantage of the long-term advantages afforded by surgical palliation,operative procedures must be performed with acceptable morbidity. The average postoperative length of hospital stay for patients who undergo surgical palliation is less than 15 days, even in those who develop minor complications. The average survival of patients who receive surgical palliation alone for nonmetastatic, unresectable pancreatic cancer is approximately 8 months. As with all treatment planning, palliative therapy for pancreatic and biliary cancer should be planned using a multidisciplinary approach, including input from the surgeon, gastroenterologist, radiologist,and medical and radiation oncologist. In this way, quality of life can be optimized in most patients with these diseases.

Cholangiocarcinoma: molecular targeting strategies for chemoprevention and therapy

Cholangiocarcinomas are devastating cancers that are increasing in both their worldwide incidence and mortality rates. The challenges posed by these often lethal biliary tract cancers are daunting, with conventional treatment options being limited and the only hope for long-term survival being that of complete surgical resection of the tumor. Unfortunately, the vast majority of patients with cholangiocarcinoma typically seek treatment with advanced disease, and often these patients are deemed poor candidates for curative surgery. Moreover, conventional chemotherapy and radiation therapy have not been shown to be effective in prolonging long-term survival, and although photodynamic therapy combined with stenting has been reported to be effective as a palliative treatment, it is not curative. Thus, there is a real need to develop novel chemopreventive and adjuvant therapeutic strategies for cholangiocarcinoma based on exploiting select molecular targets that would impact in a significant way on clinical outcome. This review focuses on potential preventive targets in cholangiocarcinogenesis, such as inducible nitric oxide synthase, cyclooxygenase-2, and altered bile acid signaling pathways. In addition, molecular alterations related to dysregulation of cholangiocarcinoma cell growth and survival, aberrant gene expression, invasion and metastasis, and tumor microenvironment are described in the context of various clinical and pathological presentations. Moreover, an emphasis is placed on the importance of critical signaling pathways and postulated interactions, including those of ErbB-2, hepatocyte growth factor/Met, interleukin-6/glycoprotein130, cyclooxygenase-2, vascular endothelial growth factor, transforming growth factor-beta, MUC1 and MUC4, beta-catenin, telomerase, and Fas pathways as potential molecular therapeutic targets in cholangiocarcinoma.

Palliative therapy for pancreatic/biliary cancer

Palliative treatment for unresectable pancreatic and biliary cancer is most typically directed at symptoms of local invasion, including obstructive jaundice, duodenal obstruction, and cancer-related pain. Surgical and nonsurgical therapeutic options should be considered depending on the individual situation. As with all treatment planning, palliative therapy should be planned using a multidisciplinary approach, including input from the surgeon, gastroenterologist,radiologist, and medical and radiation oncologist.

Therapeutic endoscopic retrograde cholangiopancreatography: what the future holds

These are exciting times for interventional endoscopists performing ERCP. The advent of noninvasive, diagnostic techniques of the pancreaticobiliary tree has resulted in a shift toward more therapeutic procedures. The combination of major technologic advances together with endoscopists' growing comfort with invasive procedures has helped to push the boundaries of endoscopic therapy. These therapies, however, should always be sanctioned by sound science and well-controlled clinical trials.

Endoscopic ultrasonography and endoscopic retrograde cholangiopancreatography imaging for pancreaticobiliary pathology: the gastroenterologist's perspective

With advances in noninvasive radiologic technology, additional adjunctive techniques are developing, and the roles for ERCP and EUS are continuously changing. In a diagnostic setting, ERCP is currently best reserved for patients with a high likelihood of needing endoscopic therapy, and EUS is especially useful for cases in which other imaging techniques have been inconclusive or are of inferior diagnostic capability. In a therapeutic setting, ERCP and EUS retain important roles in the management of both benign and malignant pancreatic and biliary disease. Certainly, technological advances also directly affect these modalities and expanded applications for ERCP and EUS for the pancreas and biliary tract are anticipated.

Palliative treatment of unresectable bile duct cancer: which stent? which approach?

Nonsurgical options for the palliative treatment of unresectable bile duct cancer are discussed. Despite all of the available approaches, the disease remains uniformly fatal. The goal of managing unresectable bile duct cancer is to treat the symptoms that still contribute to significant morbidity and mortality. Further development of new treatment strategies and modalities is needed to improve the quality of life and survival of patients with this disease.

Optimization of 5-fluorouracil (5-FU)/cisplatin combination chemotherapy with a new schedule of leucovorin, 5-FU and cisplatin (LV5FU2-P regimen) in patients with biliary tract carcinoma

BACKGROUND

Unresectable biliary tract carcinoma (BTC) is associated with a very poor prognosis. To improve efficacy and tolerance of the 5-fluorouracil (5-FU)/cisplatin combination in BTC, we designed a new therapeutic schedule, the LV5FU2-P regimen.

PATIENTS AND METHODS

Twenty-nine patients with advanced or metastatic BTC were prospectively enrolled in the study. The treatment (LV5FU2-P regimen) consisted of a biweekly administration of a 2-h infusion of leucovorin 200 mg/m(2), a 400 mg/m(2) bolus of 5-FU followed by a 22-h continuous infusion of 600 mg/m(2) 5-FU on two consecutive days and cisplatin 50 mg/m(2) on day 2. Clinical symptoms, performance and weight changes were monitored.

RESULTS

Objective responses were observed in 10 patients (34%) (95% confidence interval 23% to 45%) including one complete response and nine partial responses (stabilization 38%, progression 28%). Median progression-free survival and overall survival were 6.5 and 9.5 months, respectively. Weight gain was observed in 45% of patients and performance status improved in 60%. One patient had a grade 4 thrombocytopenia, and grade 3 toxicity occurred in 41% of patients. There were no treatment-related deaths.

CONCLUSIONS

This study, one of the largest phase II trials performed for this disease, shows that the LV5FU2-P regimen is an active and well-tolerated chemotherapy for advanced and metastatic BTC.

Endoscopic management of biliary tract disease

New investigations, evaluation of controversial issues, and advances in technology continue to shape the endoscopic management of biliary disorders. This article discusses recent literature related to the diagnosis and therapy of biliary tract disease. Specifically, the diagnosis and management of choledocholithiasis, complications of biliary endoscopy and potential preventive measures, roles for endosonography in the evaluation of biliary disease, and endoscopic therapy of postoperative liver transplantation complications are reviewed. Recent advances in biliary stents and the use of cholangioscopy in biliary disorders are also assessed.