Intraductal radiofrequency ablation for management of malignant biliary obstruction

Radiofrequency ablation via catheter and transpapillary access in patients with cholangiocarcinoma (ACTICCA-2 trial) - a multicenter, randomized, controlled, open-label investigator-initiated trial

BACKGROUND

Despite the recent advances in cancer treatment, the therapeutic options for patients with biliary tract cancer are still very limited and the prognosis very poor. More than 50% of newly diagnosed patients with biliary tract cancer are not amenable to curative surgical treatment and thus treated with palliative systemic treatment. Malignant bile duct obstructions in patients with perihilar and/or ductal cholangiocarcinoma (CCA) represents one of the most important challenges in the management of these patients, owning to the risk represented by developing life-threatening cholangitis which, in turn, limits the use of systemic treatment. For this reason, endoscopic stenting and/or bile duct decompression is the mainstay of treatment of these patients. Data on efficacy and safety of adding radiofrequency ablation (RFA) to biliary stenting is not conclusive. The aim of this multicenter, randomized trial is to evaluate the effect of intraductal RFA prior to bile duct stenting in patients with unresectable perihilar or ductal CCA undergoing palliative systemic therapy.

METHODS/DESIGN

ACTICCA-2 is a multicenter, randomized, controlled, open-label, investigator-initiated trial. 120 patients with perihilar or ductal CCA with indication for biliary stenting and systemic therapy will be randomized 1:1 to receive either RFA plus bile duct stenting (interventional arm) or bile duct stenting alone (control arm). Patients will be stratified by trial site and tumor location (perihilar vs. ductal). Both arms receive palliative systemic treatment according to the local standard of care determined by a multidisciplinary tumorboard. The primary endpoint is time to first biliary event, which is determined by an increase of bilirubin to > 5 mg/dl and/or the occurrence of cholangitis leading to premature stent replacement and/or disruption of chemotherapy. Secondary endpoints include overall survival, safety according to NCI CTCAE v5, quality of life assessed by questionnaires (EORTC QLQ-C30 and QLQ-BIL21), clinical event rate at 6 months after RFA and total days of over-night stays in hospital. Follow-up for the primary endpoint will be 6 months, while survival assessment will be continued until end of study (maximum follow-up 30 month). All patients who are randomized and who underwent endoscopic stenting will be used for the primary endpoint analysis which will be conducted using a cause-specific Cox proportional hazards model with a frailty for trial site and fixed effects for the treatment group, tumor location, and stent material.

DISCUSSION

ACTICCA-2 is a multicenter, randomized, controlled trial to assess efficacy and safety of adding biliary RFA to bile duct stenting in patients with CCA receiving palliative systemic treatment.

TRIAL REGISTRATION

The study is registered with ClinicalTrials.gov (NCT06175845) and approved by the local ethics committee in Hamburg, Germany (2024-101232-BO-ff). This manuscript reflects protocol version 1 as of January 9th, 2024.

Ablation Therapy of the Biliary Tree: Status and Comprehensive Review

Malignant biliary obstruction is typically referred to endoscopists for palliation. A curative resection is indeed rarely an option in this condition. Photodynamic therapy and radiofrequency ablation are 2 modalities that can be offered in those patients. Many studies have demonstrated improved stent patency and survival after ablation. Photodynamic therapy is unfortunately very expensive and is associated with photosensitivity; however, it transmits to the entire biliary tree. Radiofrequency ablation is more affordable and easier to apply but requires contact with the tumor to be efficient. This review explores both modalities in terms of their safety and efficacy for bile duct cancer palliation.

The Impact of Radiofrequency Ablation on Survival Outcomes and Stent Patency in Patients with Unresectable Cholangiocarcinoma: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Endoluminal biliary radiofrequency ablation (RFA) has been proposed as a palliative treatment for patients with malignant biliary obstruction (MBO) in order to improve stent patency and survival. However, the existing data on patients with inoperable extrahepatic cholangiocarcinoma (eCCA) are conflicting. We performed a meta-analysis of randomized trials comparing RFA plus stenting versus stenting alone in patients with inoperable eCCA. We searched for trials published in the PubMed/MEDLINE, Scopus, and Cochrane databases up to November 2023. Data extraction was conducted from published studies, and a quality assessment was carried out in accordance with the guidelines recommended by the Cochrane Collaboration. Hazard ratios (HRs) with 95% CI were estimated from the trials. The primary endpoints of interest were overall survival and stent patency. Out of 275 results, 5 randomized trials and 370 patients were included. While overall survival was not different between the groups (HR 0.62; 95% CI 0.36-1.07; p = 0.09; I2 = 80%;), the subgroup analysis of studies employing plastic stents showed a trend toward better survival in the RFA-treated group (HR 0.42; 95% CI 0.22-0.80; p = 0.009; I2 = 72%). Stent patency was improved in patients receiving RFA (HR 0.64; 95% CI 0.45-0.90; p = 0.01; I2 = 23%). Adverse events were not different between the groups (OR 1.21; 95% CI 0.69-2.12; p = 0.50; I2 = 0%). Despite the promising results, high heterogeneity and potential biases in the included studies suggest the need for further high-quality randomized trials to explore the potential cumulative effects of RFA on CCA treatment outcomes.

[Intraductal radiofrequency ablation under endosonography and cholangioscopy for residual adenoma of the major duodenal papilla with intraductal component]

All adenomas of the major duodenal papilla (MDP) require resection regardless of morphological structure due to high risk of malignancy. Currently, intraluminal endoscopic interventions are preferable for these adenomas. MDP neoplasms with intraductal spread (type III and IV) are of particular difficulty for endoscopic techniques. Intraductal radiofrequency ablation provides new opportunities for minimally invasive treatment of patients with MDP adenomas and intraductal component. A 72-year-old patient after previous endoscopic papillectomy for MDP adenoma admitted to the Vishnevsky National Research Medical Center of Surgery due to residual adenomatous growths within the papillectomy zone extending to the common bile duct throughout 13 mm. The patient underwent intraductal RFA under endosonography and cholangioscopy. Despite difficult localization of residual growths extending to the common bile duct, endosonography-guided intraductal RFA provided total destruction of residual tumor that was confirmed by cholangioscopy. Length of treatment was 4 months, relapse-free period - 10 months. Minimally invasive endoscopic technology for residual MDP adenoma provided good clinical results.

[Intraductal radiofrequency ablation for neoplasms of the major duodenal papilla with intraductal spread]

OBJECTIVE

To analyze the efficacy of intraductal radiofrequency ablation (RFA) for neoplasms of the major duodenal papilla with intraductal spread.

MATERIAL AND METHODS

Eleven patients with adenomas of the major duodenal papilla and intraductal spread underwent intraductal RFA between 2022 and 2023. Spread to the common bile duct ranged from 10 to 30 mm, to the main pancreatic duct - from 5 to 11 mm.

RESULTS

Technical success was achieved in all cases. Complications after intraductal RFA occurred in 4 cases (post-manipulation pancreatitis - 2 cases, repeated intraductal RFA for residual adenomatous growths - 2 cases). Technical success of stenting of the main pancreatic and common bile ducts was achieved in all cases.

CONCLUSION

Intraductal radiofrequency ablation for neoplasms of the major duodenal papilla with intraductal spread ensured complete destruction of intraductal tumor with adequate clinical effect and no need for highly traumatic surgery.

Is endoscopic radiofrequency ablation plus stent placement superior to stent placement alone for the treatment of malignant biliary obstruction? A systematic review and meta-analysis

OBJECTIVE

Malignant biliary obstruction (MBO) is a rare disease with a poor prognosis. Recent studies have shown that endoscopic radiofrequency ablation (ERFA) may improve survival. We conducted a systematic review and meta-analysis of the efficacy of ERFA in combination with biliary stent placement for the treatment of MBO.

METHODS

The study was registered in INPLASY (number 202340096). The PubMed, Cochrane Library, Web of Science, and Embase databases were searched from inception to April 2023. We selected studies comparing the efficacy of ERFA plus stent placement with stent placement alone. The primary outcomes were pooled hazard ratios (HRs) for overall survival and stent patency; the secondary outcomes were the odds ratios (ORs) for adverse events.

RESULTS

Eleven studies (four randomized controlled trials and seven observational studies) were included in the meta-analysis. Pooled analysis showed a difference in survival time between the two groups (HR 0.65, 95% confidence interval [CI] 0.58-0.73, I2 = 40%). However, there were no differences in the duration of stent patency or the incidence of adverse events (HR 1.04, 95% CI 0.84-1.29, I2 = 46%; OR 1.41, 95% CI 1.02-1.96, I2 = 29%).

CONCLUSIONS

ERFA has a significant survival benefit for MBO, but does not increase the risk of adverse events.

Balloon-assisted laser application for endoscopic treatment of biliary stricture

OBJECTIVES

Malignant biliary stricture is a ductal narrowing of the bile duct that is often diagnosed at an advanced stage, leading to difficulty in resection. The current study aims to evaluate the feasibility of endobiliary laser treatment by quantifying the extent of coagulative necrosis in tissue under various conditions.

METHODS

Ex vivo and in vivo porcine bile tissues were used for endobiliary laser treatment to characterize the dosimetric responses of the tissue to various treatment conditions: power level, irradiation time, and number of treatments. 532 nm laser light was coupled with a balloon-integrated diffusing applicator (BDA) to deliver the laser light endoscopically for tissue coagulation. The coagulated regions (maximum length and depth) in the treated tissues were evaluated histologically for quantitative comparison.

RESULTS

Dosimetric evaluations with ex vivo liver tissue confirmed that both maximum length and depth of coagulative necrosis (CN) increased with applied power and number of treatments. Ex vivo bile duct tests demonstrated that BDA-assisted laser treatment at 10 W for 12 s reproducibly yielded CN with a length of 5.8 ± 1.6 mm and a depth of 0.6 ± 0.2 mm. In vivo tests presented that endoscopic laser treatment using the BDA created CN on the ductal surface without any perforation. Microscopic examinations revealed that a dense inflammatory cell infiltration and eosinophilic area in the in vivo treated tissue. The extent of CN in the in vivo tissue was 40% longer and 120% deeper (length: 8.1 ± 0.7 mm; depth: 1.3 ± 0.2 mm), compared to that in the ex vivo tissue.

CONCLUSION

BDA-assisted laser treatment could be a feasible option for endoscopic treatment of biliary stricture with uniform ablation at the circumference of bile duct. Further in vivo studies will be performed in a large number of stricture-developed porcine models to examine both efficacy and safety of the proposed endobiliary laser treatment for clinical translations.

Long-term Outcomes of Endoscopic Intraductal Radiofrequency Ablation for Ampullary Adenoma with Intraductal Extension after Endoscopic Snare Papillectomy

Background/Aims

There are limitations in treating ampullary adenomas with intraductal extension using conventional endoscopic modalities. Endoscopic intraductal radiofrequency ablation (ID-RFA) may be useful for treating intraductal (common bile duct [CBD] and/or pancreatic duct [PD]) extensions of ampullary adenomas, but long-term data are lacking. We thus evaluated the long-term outcomes of endoscopic ID-RFA for managing ampullary adenomas with intraductal extension.

Methods

Prospectively collected endoscopic ID-RFA database at Asan Medical Center was reviewed to identify consecutive patients with ampullary adenoma who underwent ID-RFA for intraductal extension between January 2018 and August 2021. Technical success, short-term and long-term clinical success, and adverse events were evaluated.

Results

A total of 29 patients (14 CBD, 1 PD, and 14 CBD and PD) were analyzed. All patients had undergone endoscopic snare papillectomy prior to ID-RFA. A median of one session of ID-RFA (range, 1 to 3) for residual or relapsed intraductal extension of ampullary adenoma were successfully performed (technical success=100%). Both biliary and pancreatic stenting were routinely performed after ID-RFA to prevent ductal stricture. After a median follow-up of 776 days (interquartile range, 470 to 984 days), the short-term and long-term clinical success rates were 93% and 76%, respectively. Seven patients experienced procedural adverse events and three patients developed ductal strictures.

Conclusions

Endoscopic ID-RFA showed good long-term outcomes in treating residual or relapsed ampullary adenomas with intraductal extension. Repeated ID-RFA may be considered as an option for managing recurrence. Further studies are needed to standardize the procedure.

Impact of endobiliary radiofrequency ablation on survival of patients with unresectable cholangiocarcinoma: a narrative review

Cholangiocarcinoma (CCA) is a rare cancer originating from the biliary epithelium and accounts for about 3% of all gastrointestinal malignancies. Unfortunately, the majority of patients are not eligible for surgical resection at the time of diagnosis, because of the locally advanced stage or metastatic disease. The overall survival time of unresectable CCA is generally less than 1 year, despite current chemotherapy regimens. Biliary drainage is often required as a palliative treatment for patients with unresectable CCA. Recurrent jaundice and cholangitis tend to occur because of reobstruction of the biliary stents. This not only jeopardizes the efficacy of chemotherapy, but also causes significant morbidity and mortality. Effective control of tumor growth is crucial for prolonging stent patency and consequently patient survival. Recently, endobiliary radiofrequency ablation (ERFA) has been experimented as a treatment modality to reduce tumor mass, and delay tumor growth, extending stent patency. Ablation is accomplished by means of high-frequency alternating current which is released from the active electrode of an endobiliary probe placed in a biliary stricture. It has been shown that tumor necrosis releases intracellular particles which are highly immunogenic and activate antigen-presenting cells, enhancing local immunity directed against the tumor. This immunogenic response could potentially enhance tumor suppression and be responsible for improved survival of patients with unresectable CCA who undergo ERFA. Several studies have demonstrated that ERFA is associated with an increased median survival of approximately 6 months in patients with unresectable CCA. Furthermore, recent data support the hypothesis that ERFA could ameliorate the efficacy of chemotherapy administered to patients with unresectable CCA, without increasing the risk of complications. This narrative review discusses the results of the studies published in recent years and focuses on the impact that ERFA could have on overall survival of patients with unresectable cholangiocarcinoma.

Efficacy and Safety of Radiofrequency Ablation Plus Stent Versus Stent-alone Treatments for Malignant Biliary Strictures: A Systematic Review and Meta-analysis

BACKGROUND/AIMS

Malignant biliary strictures (MBS) are very aggressive and cannot be diagnosed in the early stages due to their asymptomatic nature. Stenting the stricture area of the biliary tree is palliative treatment but has poor survival time. Radiofrequency ablation plus stent (RFA+S) have been recently used to improve the survival and stent patency time in patients with MBS. In this systematic review and meta-analysis, we tried to evaluate the efficacy and safety of radiofrequency ablation.

MATERIALS AND METHODS

Study search up to December 2021 was performed in different medical databases such as PubMed, Web of Science, and Cochrane library, etc. We selected eligible studies reporting survival time, stent patency time, and adverse events in patients with MBS. We compare the outcomes of RFA+S and stent-alone treatment groups.

RESULTS

A total of 15 studies (6 randomized controlled trials and 9 observational studies) with 1815 patients were included for meta-analysis of which 701 patients were in RFA+S group and 1114 patients in the stent-alone group. Pooled mean difference of survival time was 2.88 months (95% CI: 1.78-3.97) and pooled mean difference of stent patency time was 2.11 months (95% CI: 0.91-3.30) and clinical success risk ratio was 1.05 (95% CI: 1.01-1.09). Risk ratios for adverse events are given; Bleeding 0.84 (95% CI: 0.34-2.11), abdominal pain 1.06 (95% CI: 0.79-1.40), pancreatitis 0.93 (95% CI: 0.43-2.01), cholangitis 1.07 (95% CI: 0.72-1.59), and stent dysfunction 0.87 (95% CI: 0.70-1.07).

CONCLUSIONS

Radiofrequency ablation is involved in increased survival and stent patency time for MBS patients. With the help of better techniques, adverse events can be limited.

[Complex endoscopic treatment of a patient with a large adenoma of the major duodenal papilla, choledocholithiasis and stricture of the common bile duct]

Incidence of adenomas of the major duodenal papilla has increased in recent years due to widespread endoscopic screening. These adenomas require resection due to high risk of malignant transformation. Currently, minimally invasive endoscopic interventions are often considered as an alternative to surgical treatment. Combination of major duodenal papilla neoplasms with choledocholithiasis and bile duct strictures are particularly difficult for endoscopic treatment. A 56-year-old patient underwent complex endoscopic treatment for a large adenoma of the major duodenal papilla spreading to duodenal walls and distal segment of the common bile duct combined with choledocholithiasis and stricture of the common bile duct. The patient underwent complex minimally invasive treatment with endoscopic lithoextraction, fragment-by-fragment removal of the neoplasm with intra-ductal ablation of residual adenomatous tissue and subsequent staged biliary stenting for the stricture of the common bile duct, as well as stenting of the main pancreatic duct for prevention of pancreatitis. An integrated approach to the treatment of a patient with a large adenoma of the major duodenal papilla, choledocholithiasis and stricture of the common bile duct provided clinical success without complications and the need for long-term rehabilitation.

Optimal reproduction of a porcine benign biliary stricture model using endobiliary radiofrequency ablation

The use of endobiliary radiofrequency ablation (RFA) to generate a benign biliary stricture (BBS) model has a significant reproducibility problem. The aims of this animal study were to create an optimal BBS model using endobiliary RFA and determine the best way to develop it. The first step was performed on the common bile duct (CBD) of 10 miniature pigs using endoscopic RFA with a target temperature-controlled mode (80 ℃, 7 W for 90 s). The second step was performed on the CBD of five miniature pigs to understand more about the time-dependent changes in BBS development and the causes of adverse events. Using the conditions and techniques identified in the previous steps, the third step was conducted to create an optimal BBS model in 12 miniature pigs. In the first trial, four out of 10 animals died (40%) after the procedure due to cholangitis-induced sepsis. Based on this, biliary obstruction was prevented in further steps by placing a biliary plastic stent after RFA application. Histologic examinations over time showed that a severe abscess developed at the RFA application site on the fifth day, followed by fibrosis on the tenth day, and completion on the twentieth day. In the third trial, 11 animals survived (91.7%), the average BBS fibrotic wall thickness was 1107.9 µm (763.1–1864.6 µm), and the degree of upstream biliary dilation was 14.4 mm (11.05–20.7 mm). In conclusion, endobiliary RFA combined with a biliary plastic stent resulted in a safe and reproducible BBS animal model.

Silver Nanofunctionalized Stent after Radiofrequency Ablation Suppresses Tissue Hyperplasia and Bacterial Growth

Intraductal radiofrequency (RF) ablation combined with placement of a self-expandable metal stent (SEMS) for malignant biliary obstruction has risks such as stent- and heat-induced biliary sludge and restenosis. Here, we investigated the efficacy of a silver nanoparticles (AgNPs)-coated SEMS to inhibit tissue hyperplasia and bacterial growth caused by RF ablation with stent placement in the rabbit bile duct. The release behavior and antibacterial effects of AgNPs-coated SEMSs were evaluated. Then, SEMSs were successfully placed in all rabbits immediately after RF ablation. Ag ions were rapidly released at the beginning and then showed a gradual release behavior. The AgNPs-coated SEMS significantly inhibited bacterial activity compared to the uncoated SEMS (p < 0.05). Cholangiography and histological examination confirmed that the level of tissue hyperplasia was significantly lower in the AgNPs group than in the control group (all p < 0.05). Immunohistochemistry analyses revealed that TUNEL-, HSP 70-, and α-SMA-positive areas were significantly lower in the AgNPs group than in the control group (all p < 0.05). Intraductal RF ablation combined with nanofunctionalized stent placement represents a promising new approach for suppressing thermal damage as well as stent-induced tissue hyperplasia and bacterial growth.

Advancements in Endoscopic Biliary Interventions by Gastroenterology

Endoscopic retrograde cholangiopancreatography (ERCP) is an endoscopic technique in which a specialized side-viewing endoscope is guided into the duodenum, allowing for instruments to access the biliary and pancreatic ducts. ERCP was initially developed as a diagnostic tool as computed tomography was in its infancy during that time. ERCP has evolved since its inception in the 1960s to becoming not only a valuable diagnostic resource but now an effective therapeutic intervention in the treatment of various biliary disorders. The most common biliary interventions performed by ERCP include the management of biliary obstructions for benign and malignant indications. Additionally, endoscopic ultrasound (EUS) has been increasingly utilized in diagnosing and intervening on pancreaticobiliary lesion. This article will discuss the various methods currently available for various endoscopic biliary interventions and future interventional techniques. For the management of biliary strictures, EUS can be utilized with fine need aspiration, while ERCP can be used for the placement of various stents and diagnostic modalities. Another example is radiofrequency ablation, which can be used for the treatment of hilar strictures. Achieving bile duct access can be challenging in patients with complicated clinical scenarios; other techniques that can be used for bile duct access include EUS-guided rendezvous approach, transluminal approach, Choleodochoduodenostomy, and hepatogastrostomy, along with gaining access in complicated anatomy such as in patients with Rou-en-Y anatomy. Another useful endoscopic tool is nonsurgical drainage of the gallbladder, which can be a suitable option when patients are not optimal surgical candidates. There has also been an increase in outpatient utilization of ERCP, which was previously seen as a predominantly inpatient procedure in the past. Possible future evolutions of biliary interventions include robotic manipulation of a duodenoscope and direct infusion of chemotherapeutic or immunomodulatory agents into the pancreaticobiliary tree. These advancements will depend on parallel advancements in other imaging and laboratory as well as breakthrough technology or techniques by other disciplines including interventional radiology and minimally invasive surgery.

Acute and subacute effects of irreversible electroporation on normal common bile ducts in a rabbit model

BACKGROUND/PURPOSE

This study aimed to evaluate the acute and subacute effects of irreversible electroporation (IRE) on normal common bile ducts (CBDs).

METHODS

Cell susceptibility to IRE was assessed in vitro with cholangiocarcinoma and normal cell lines. The electric field and temperature distributions were evaluated with a two-dimensional simulation model of bile duct. In vivo bile duct IRE was performed in 28 adult rabbits.

RESULTS

Different cells showed different susceptibility to the effect of IRE, cancer cell line HUCC-T1 was the least sensitive to IRE. Simulations predicted the distributions of electric field and temperature during the IRE process, and the maximum temperature of tissue was below 43℃. Complications were observed in 8/28 animals (biliary dilatation, n = 4; biliary stricture, n = 4) by postoperative days 7, 14, and 28. Histopathological analyses revealed complete cell death with bile duct wall integrity. Bile duct epithelial recovery was completed between post-IRE days 14-28.

CONCLUSIONS

The normal CBD retains the lumen wall integrity following IRE with immediate periductal placement of the electrode. However, the risk of biliary dilatation and stricture is a reminder that the parameters of IRE need to be determined more precisely to ensure the treatment efficacy and reduce the risk of collateral damage.

Usefulness of intraductal RFA in patients with malignant biliary obstruction

BACKGROUND/AIMS

Intraductal radiofrequency ablation (ID-RFA) is a novel therapy for unresectable malignant biliary obstructions. ID-RFA for perihilar lesions is associated with a high risk of adverse events. We aimed to evaluate the feasibility and efficacy of temperature-controlled ID-RFA for perihilar malignant biliary obstruction.

METHODS

Sixteen patients with pathologically proven perihilar cholangiocarcinoma were prospectively enrolled to evaluate the feasibility of hilar ID-RFA. Clinical efficacy and outcomes were subsequently evaluated in a multicenter retrospective cohort.

RESULTS

Nine of the 16 patients in the prospective cohort had Bismuth type IV and 7 had type IIIA perihilar cholangiocarcinoma. The median length of stricture was 34.5 mm. The median number of ID-RFA sessions was three, and all sessions were technically and functionally successful without severe adverse events. Clinical outcomes were assessed using a multicenter hilar ID-RFA cohort of 21 patients; the median stent patency and overall survival were 90 days (range: 35-483 days) and 147 days (range: 92-487 days), respectively. An approximate 16-month patency of the bile duct was maintained in one patient who had an intraductal growth pattern. In a comparison of the self-expandable metallic stent (SEMS) and plastic stent (PS) after hilar ID-RFA, no differences in stent patency (89 vs 90.5 days, respectively; P = .912) and adverse events (20.0% vs 10%, respectively; P = .739) were observed.

CONCLUSIONS

ID-RFA at 7 W for 120 seconds is safe and feasible in patients with advanced perihilar cholangiocarcinoma. After ID-RFA, SEMS and PS placement showed comparable patency and survival rates.

TRIAL REGISTRATION NUMBER

KCT0003223.

Efficacy and safety of palliative endobiliary radiofrequency ablation using a novel temperature-controlled catheter for malignant biliary stricture: a single-center prospective randomized phase II TRIAL

BACKGROUND

Endobiliary radiofrequency ablation (EB-RFA) has emerged as a palliative treatment for malignant biliary strictures (MBSs); however, concerns about complications related to thermal injury remain. In this study, we evaluated the efficacy and safety of EB-RFA with a novel catheter for MBS.

METHODS

Patients with inoperable cancer causing MBS were randomly assigned to either the radiofrequency ablation (RFA) group or the non-RFA group. The RFA group underwent EB-RFA at the stricture site with a temperature-controlled catheter (ELRA™; STARmed Co., Goyang, Korea) followed by deployment of a self-expanding metal stent (SEMS). For the non-RFA group, only SEMS placement was performed. The duration of stent patency, overall survival (OS), and 30-day complication rate were evaluated. This trial was registered at ClinicalTrials.gov (number NCT02646514).

RESULTS

A total of 48 patients were enrolled (24 in each group). During a median follow-up period of 135.0 days (RFA group) and 119.5 days (non-RFA group), the 90-day stent patency rate, median duration of stent patency, and median OS were not different between the groups (58.3% vs. 45.8% [P = 0.386], 132.0 days vs. 116.0 days [P = 0.440], and 244.0 days vs. 180.0 days [P = 0.281], respectively). In the RFA group, procedure-related complications including thermal injury-related complications, such as bile duct perforation or hemobilia, were not reported. The early complication (< 7 days) rates were not different between the groups (4.2% vs. 12.5%, P = 0.609), and there were no late complications (7-30 days) in both groups.

CONCLUSION

EB-RFA with a temperature-controlled catheter followed by SEMS placement for patients with inoperable MBS can be safe and feasible with acceptable biliary patency.

Ablative therapies for hepatic and biliary tumors: endohepatology coming of age

Ablative therapies refer to minimally invasive procedures performed to destroy abnormal tissue that may arise with many conditions, and can be achieved clinically using chemical, thermal, and other techniques. In this review article, we explore the different ablative therapies used in the management of hepatic and biliary malignancies, namely hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), with a particular focus on radiofrequency ablation (RFA) and photodynamic therapy (PDT) techniques.

Endoscopic Retrograde Cholangiopancreatography-Guided Ablation for Cholangiocarcinoma

Most patients with perihilar cholangiocarcinoma present with surgically unresectable disease owing to the insidious nature of this malignancy. Relief of malignant perihilar biliary obstruction is a key aspect of cholangiocarcinoma. Although palliative stenting using uncovered metal stents has been advocated in patients with unresectable malignant perihilar biliary strictures, several endoscopic retrograde cholangiopancreatography-guided ablative modalities have emerged. Palliative photodynamic therapy, radiofrequency ablation, and intraluminal brachytherapy have been associated with improved stent patency and survival, although the ideal treatment approach remains unclear. This article reviews the published evidence for using each of these endobiliary ablative modalities in this difficult-to-treat patient population.

Radiofrequency and malignant biliary strictures: An update

Malignant biliary strictures are usually linked to different types of tumors, mainly cholangiocarcinoma, pancreatic and hepatocellular carcinomas. Palliative measures are usually adopted in patients with nonresectable or borderline resectable biliary disease. Stent placement is a well-known and established treatment in patients with unresectable malignancy. Intraductal radiofrequency ablation (RFA) represents a procedure that involves the use of a biliary catheter device, via an endoscopic approach. Indications for biliary RFA described in literature are: Palliative treatment of malignant biliary strictures, avoiding stent occlusion, ablating ingrowth of blocked metal stents, prolonging stent patency, ablating residual adenomatous tissue after endoscopic ampullectomy. In this mini-review we addressed focus on technical success defined as deployment of the RF catheter, virtually succeeded in all patients included in the studies. About efficacy, three main outcome measures have been contemplated: Biliary decompression and stent patency, survival. Existing studies suggest a beneficial effect on survival and stent patency with RFA, but current impression is limited because most of studies have been performed using a retrospective design, on diminutive and dissimilar cohorts of patients.

Comparison of two porcine benign esophageal stricture models using radiofrequency ablation and endoscopic submucosal tunnel dissection

BACKGROUND/AIMS

Large-animal benign esophageal stricture (BES) models are needed for the development of new endoscopic therapies and related devices. This study was undertaken to develop and compare swine BES models produced by radiofrequency ablation (RFA) or endoscopic submucosal tunnel dissection (ESTD).

MATERIALS AND METHODS

RFA and ESTD were each performed on three pigs. Follow-up endoscopy and esophagography were performed immediately after the procedures and then 2, 3, and 4 weeks later. Four weeks after the procedures, all animals were sacrificed, and gross and histologic examinations were performed.

RESULTS

BES was successfully achieved in both the RFA and ESTD groups, and all animals survived without any serious adverse events during the 4-week follow-up period. Mean procedural times were 9.3 min for RFA and 89.3 min for ESTD. ESTD caused long segment strictures whose average length was 4.5 cm, whereas RFA produced short strictures whose average length was 1.4 cm. BES began to form 2 weeks after both procedures. Degrees of strictures were similar at 3 and 4 weeks in the ESTD group; however, it started deteriorating over time in the RFA group. Histologic examinations showed that ESTD caused inflammation and fibrosis in the submucosal layer, whereas RFA induced extensive inflammation in the submucosal and muscularis propria layers.

CONCLUSION

BES was successfully achieved using RFA or ESTD in swine without serious complications. The methods have different characteristics; therefore, researchers should choose the method more appropriate for their purposes.

Efficacy and safety of endobiliary radiofrequency ablation for the eradication of residual neoplasia after endoscopic papillectomy: a multicenter prospective study

BACKGROUND AND AIMS

Endobiliary dysplasia may persist after endoscopic papillectomy. Intraductal radiofrequency ablation (ID-RFA) is a potential alternative to complementary surgery. The aim of this study was to evaluate the efficacy and safety of ID-RFA for the treatment of adenomatous intraductal residue after endoscopic papillectomy.

METHODS

A prospective open-label multicenter study included patients with histologically proven endobiliary adenoma remnant (ductal extent <20 mm) after endoscopic papillectomy for ampullary tumor. RFA (effect 8, power 10 W, 30 seconds) was performed during ERCP. Biliary ± pancreatic stent was placed at the end of the procedure. Endpoints were (1) the rate of residual neoplasia (ie, low-grade dysplasia [LGD], high-grade dysplasia [HGD], or invasive carcinoma) at 6 and 12 months, (2) rate of surgery, and (3) adverse events.

RESULTS

Twenty patients (67 ± 11 years of age, 12 men) were included. The endobiliary adenoma was in LGD in 15 patients and HGD in 5 patients. All underwent 1 successful ID-RFA session with biliary stent placement and recovered uneventfully. Five (25%) received a pancreatic stent. The rates of residual neoplasia were 15% and 30% at 6 and 12 months, respectively. Only 2 patients (10%) were referred for surgery. Eight patients (40%) experienced at least 1 adverse event between ID-RFA and 12 months of follow-up. No major adverse event occurred. HGD at inclusion was associated with higher dysplasia recurrence at 12 months (P = .01).

CONCLUSIONS

ID-RFA of residual endobiliary dysplasia after endoscopic papillectomy can be offered as an alternative to surgery, with a 70% chance of dysplasia eradication at 12 months after a single session and a good safety profile. Patient follow-up remains warranted after ID-RFA. (Clinical trial registration number: NCT02825524.).

New Indications for Endoscopic Radiofrequency Ablation

Radiofrequency ablation (RFA) is a well-established treatment for several benign, premalignant, and malignant disorders. Although the role of RFA has been clearly defined, new indications for luminal and extraluminal applications of endoscopic RFA-directed therapies have emerged. RFA has recently produced promising results in patients with a variety of gastrointestinal and hepatopancreatobiliary pathologies. For example, endoscopic RFA has been used to treat patients with gastric antral vascular ectasia, chronic radiation proctitis, malignant biliary strictures, and ampullary adenomas with intraductal extension. Furthermore, endoscopic ultrasound-guided RFA appears to be an effective, minimally invasive treatment for ablation of solid and cystic lesions-particularly in the pancreas. We review the newer indications for RFA and discuss potential limitations of endoscopic RFA.

Top Ten Tips Palliative Care Clinicians Should Know About Interventional Symptom Management Options When Caring for Patients with Gastrointestinal Malignancies

Patients diagnosed with advanced stages of gastrointestinal (GI) malignancies are often quite symptomatic, with symptoms primarily related to anatomic sites of obstruction. Endoscopic approaches to the palliation of GI malignancies have begun to overtake surgical approaches as first line in interventional management. We brought together a team of interventional gastroenterologists and palliative care experts to collate practical pearls for the types of endoscopic interventions used for symptom management in patients with GI malignancies. In this article, we use a "Top 10" format to highlight issues that may help palliative care physicians recognize common presentations of advanced GI malignancies, address interventional approaches to improve symptom burden, and improve the quality of shared decision making and goals-of-care discussions.

Evaluation of Effects of Radiofrequency Ablation of Ex vivo Liver Using the 1-Fr Wire Electrode

BACKGROUND AND STUDY AIMS

Percutaneous and intraoperative radiofrequency ablation (RFA) has become a valued tool in the management of primary and secondary hepatic lesions. A recent FDA-approved endoscopic ultrasound (EUS)-guided RFA probe now offers promise to help manage such lesions. However, there are no data to determine the ideal power setting and duration of ablation needed to effectively treat hepatic masses. The aim of the study was to evaluate the macroscopic zone of hepatic injury for EUS-RFA using a variety of settings within a fresh porcine hepatic specimen.

METHODS

RFA was performed using the Habib EUS-RFA needle (EMcision Ltd, London, UK) which is a 1-Fr wire (0.33 mm, 0.013 inch) with a working length of 190 cm. A step by step approach to deliver radiofrequency energy at 5, 10, 15, 20, and 50 W of power and 10, 30, 60, 90, 120, and 300 seconds, respectively, was followed. Macroscopic and microscopic findings of the ablation zone were evaluated at each setting.

RESULTS

The maximal zone (diameter, 8.2±0.14 mm; length, 20.85±0.21 mm) of coagulative necrosis was achieved using an ablation power of 10 W for duration of 90 seconds. Notably, increased power settings resulted in an unexpected and diminished effect on tissue destruction.

CONCLUSIONS

Our findings support the use of 10 W power for 90 seconds for maximum ablation in the liver. Our data also provide initial guidance and alternate settings to be considered when performing EUS-RFA to adjust the ablation power and duration to match the lesion size, shape, and risk of injury to adjacent structures.

Percutaneous intraductal radiofrequency ablation in the management of unresectable Bismuth types III and IV hilar cholangiocarcinoma

Purpose

To assess the feasibility and safety of percutaneous intraductal radiofrequency ablation (RFA) for unresectable Bismuth types III and IV hilar cholangiocarcinoma.

Results

Percutaneous intraductal RFA combined with metal stent placement was successful in all patients without any technical problems; the technical success rate was 100%. Chemotherapy was administered to two patients. After treatment, serum direct bilirubin levels were notably decreased. Six patients died during the follow-up period. Median stent patency from the time of the first RFA and survival from the time of diagnosis were 100 days (95% confidence interval (CI), 85–115 days) and 5.3 months (95% CI, 2.5–8.1 months), respectively. No acute pancreatitis, bile duct bleeding and perforation, bile leakage, or other severe complications occurred. Four cases of procedure-related cholangitis, three cases of postoperative abdominal pain, and five cases of asymptomatic transient increase in serum amylase were observed. One patient who presented with stent blockage 252 days' post-procedure underwent repeat ablation.

Materials and Methods

Between September 2013 and May 2015, nine patients with unresectable Bismuth types III and IV hilar cholangiocarcinoma who were treated with percutaneous intraductal RFA combined with metal stent placement after the percutaneous transhepatic cholangial drainage were included in the retrospective analysis. Procedure-related complications, stent patency, and survival after treatment were investigated.

Conclusion

Percutaneous intraductal RFA combined with metal stent placement is a technically safe and feasible therapeutic option for the palliative treatment of unresectable Bismuth types III and IV hilar cholangiocarcinoma. Its long-term efficacy and safety is promising, but needs further study via randomized and prospective trials that include a greater number of patients.

Laser ablation of the biliary tree: in vivo proof of concept as potential treatment of unresectable cholangiocarcinoma

OBJECTIVES

The palliative treatment of cholangiocarcinoma is based on stent placement with well-known procedure-related complications. Consequently, alternative energy-based techniques were put forward with controversial long-term results. This study aims to evaluate the safety and effectiveness of biliary tree laser ablation (LA) in terms of: (i) absence of perforation, (ii) temperature increase, (iii) induced thermal damage in in vivo models.

MATERIALS AND METHODS

The common bile duct and cystic ducts of two pigs were ablated with a diode laser (circumferential irradiation pattern) for 6 and 3 min at 7 W. Laser settings were chosen from previous ex vivo experiments. Local temperature was monitored through a fibre Bragg grating (FBG) sensor embedded into the laser delivery probe. Histopathological analysis of the ablated specimen was performed through in situ endomicroscopy, haematoxylin and eosin (H&E) and nicotinamide adenine dinucleotide (NADH) stains.

RESULTS

Temperature reached a plateau of 53 °C with consequent thermal damage on the application area, regardless of laser settings and application sites. No perforation was detected macroscopically or microscopically. At the H&E stain, wall integrity was always preserved. The NADH stain allowed to evaluate damage extension. It turned out that the ablation spreading width depended on application time and duct diameter. In situ endomicroscopy revealed a clear distinction between ablated and non-ablated areas.

CONCLUSIONS

The temperature distribution obtained through LA proved to induce a safe and effective intraductal coagulative necrosis of biliary ducts. These results represent the basis for further experiments on tumour-bearing models for the treatment of obstructive cholangiocarcinoma.

Interventional radiofrequency ablation: A promising therapeutic modality in the management of malignant biliary and pancreatic duct obstruction

Background: Malignant biliary and/or pancreatic obstruction has often encountered in the advanced stages of periampullary and cholangicarcinomas. Habib^TM Radiofrequency (RF) ablation has been successfully used in the management of various cancers of liver and pancreas. Percutaneous HPB probe (EMcision Ltd, London, UK) is a new addition to this class of tools. It is an endoluminal Radiofrequency (RF) catheter which works on the principle of ablation and induces coagulative necrosis to recanalize the obstructed duct. The aim of this study is to address the technical details of canalization, feasibilities and outcomes of percutaneous endo-luminal Radiofrequency (RF) catheter in patients with unresectable malignancy with obstructed bile and pancreatic duct (PD). Material and Method: A total of 134 patients with inoperable malignant obstruction of biliary and PD underwent RF based percutaneous endoluminal RF ablation in a tertiary referral centre between December 15^th, 2010 to August 7^th, 2015. This device was used in a sequential manner with an intent to recanalize the obstructed. Following the initial catheter drainage of the duct, subsequent percutaneous endobiliary RF ablation, the metallic stent was placed to recanalize the obstructed bile and PD secondary to unresectable malignancy under real-time fluoroscopic guidance. Results: The percutaneous RF based ablation of obstructed bile duct and PD with metallic stent placement was successfully achieved in 130 (97.01%) cases. The three failures were noted in cases of biliary obstruction whilst, one with PD obstruction. The patency restored in 124 and patients, where the procedure was successfully completed and revealed clinical improvement reported. Conclusion: The percutaneous endoluminal RF based ablation of obstructed duct with metallic stent placement appeared to be a safe, effective procedure and may improve survival in patients with advanced stage cancer presenting with biliary and PD obstruction. Considering the above mentioned evidence, this modality may stand ahead of stenting alone. This could be considered as viable modality in management of such patients where very limited treatment options are available.

Evaluation of the safety of endoscopic radiofrequency ablation for malignant biliary stricture using a digital peroral cholangioscope (with videos)

BACKGROUND AND AIM

The clinical impact of catheter-based radiofrequency ablation (RFA) under endoscopic retrograde cholangiopancreatography (ERCP) guidance has recently been reported; however, severe adverse events have also been noted. If tumor is not present in the biliary tract, severe adverse events such as perforation or bleeding as a result of vessel injury around the biliary tract may occur. In addition, the effectiveness of RFA may not be sufficient based solely on radiographic guidance. The aim of the present study was to evaluate the actual feasibility of intraductal RFA by peroral cholangioscope (POCS) evaluation before/after RFA.

METHODS

In this retrospective study carried out between July and September 2016, consecutive patients who underwent RFA for malignant biliary stricture and POCS evaluation before/after RFA were enrolled. Primary endpoint of this study was technical feasibility of RFA, which was evaluated by POCS. Secondary endpoints were rates and types of adverse event.

RESULTS

A total of 12 consecutive patients were retrospectively enrolled in this study. Stent placement using uncovered metal stents had been previously done in six patients before RFA. Tumor was seen in the biliary tract in all patients. RFA was technically successful in all patients, and clinical success was confirmed in all patients by POCS imaging. Adverse events were seen in only one patient. Median stent patency was 154 days.

CONCLUSIONS

RFA for malignant biliary stricture may be safe. To confirm the feasibility and efficacy of RFA, additional cases, prospective studies, and a comparison study between with and without endobiliary RFA are needed.

Bile Duct Patency Maintained after Intraductal Radiofrequency Ablation in a Case of Hepatocellular Cholangiocarcinoma with Bile Duct Invasion

Combined hepatocellular-cholangiocarcinoma (HCC-CC) with bile duct invasion (BDI) is rare. In unresectable cases, biliary stent placement and photodynamic therapy (PDT) are used for resolving obstructive jaundice. However, stent occlusion remains problematic, and PDT is expensive and time-consuming. Intraductal radiofrequency ablation (RFA) is an emerging procedure for palliation in these patients. It has potential benefits including less expense, lower rates of severe complication, longer maintenance of ductal patency, and easier technique compared with PDT or stenting alone. We report a 67-year-old man who underwent repeated intraductal RFA for HCC-CC and HCC with BDI, for whom bile duct patency was maintained without additional biliary procedures.

Radiofrequency ablation for intraductal extension of ampullary neoplasms

BACKGROUND AND AIMS

Extension of ampullary adenomas into the common bile duct (CBD) or pancreatic duct (PD) may be difficult to treat endoscopically. We evaluated the feasibility, safety, and efficacy of endoscopic radiofrequency ablation (RFA) in the management of ampullary neoplasms with intraductal extension.

METHODS

This was a multicenter, retrospective analysis of all patients with intraductal extension of ampullary neoplasms treated with endoscopic RFA between February 2012 and June 2015. Treatment success was defined as the absence of detectable intraductal polyps by ductography, visual inspection, and biopsy sampling.

RESULTS

Fourteen patients with adenoma extension into the CBD (13 ± 7 mm, n = 14) and PD (7 ± 2 mm, n = 3) underwent a median of 1 RFA sessions (range, 1-5). Additional modalities (thermal probes, argon plasma coagulation, and/or photodynamic therapy) were also used in 7 patients, and prophylactic stents were routinely placed. Thirteen assessable patients underwent a median of 2 surveillance ERCPs after completion of treatment over a median follow-up of 16 months (range, 5-46), with intraductal biopsy specimens showing no neoplasm in 12 patients at the conclusion of endoscopic treatment. Treatment success was achieved in 92%, including 100% of those treated with RFA alone. Adverse events occurred in 43% and included ductal strictures (5 patients) and retroduodenal abscess (1 patient), all of which were successfully treated endoscopically.

CONCLUSIONS

Endoscopic RFA, alone or in combination with other modalities, may effectively treat intraductal extension of ampullary neoplasms. Ductal strictures were common after RFA but responded to endoscopic stent therapy. RFA may be appropriate in selected patients, particularly when the main treatment alternative is pancreaticoduodenectomy.

Endoscopic Radiofrequency Ablation of the Pancreas

Radiofrequency ablation (RFA) is a well-established technique to ablate dysplastic and neoplastic tissue via local thermal coagulative necrosis. Despite the widespread use in management of several cancers, the application of RFA in pancreas has been limited due to the increased risks of complications from the increased sensitivity of pancreatic tissue to thermal injury and proximity to vascular and biliary structures. RFA has been successfully used during laparotomy for locally advanced pancreatic carcinoma but requires an invasive approach. Endoscopic ultrasound-guided RFA offers the best combination of excellent visualization, real-time imaging guidance, and precise localization with minimal invasiveness. Several animal and human studies have demonstrated the technical feasibility and safety of endoscopic RFA in the pancreas. This article provides a comprehensive review of endoscopic RFA in the management of pancreatic lesions.

Safety and effectiveness of endobiliary radiofrequency ablation according to the different power and target temperature in a swine model

BACKGROUND AND AIM

Endobiliary radiofrequency ablation (EB-RFA) is a new endoscopic palliation and adjunctive tool. Although EB-RFA is performed worldwide, a possibility of iatrogenic thermal injury leading to perforation or bleeding still remains. Therefore, we aimed to assess the effects of thermal and coagulation injury after in vivo EB-RFA using a new catheter with a temperature sensor in a swine model.

METHODS

Twelve mini pigs were divided into four groups according to power (33 mm 10 W electrode vs. 18 mm 7 W electrode) and RFA target temperature (75°C vs. 80°C). All mini pigs underwent endoscopic retrograde cholangiography and target temperature controlled EB-RFA for 120 s. Additional cholangiogram was taken immediately after RFA, and all pigs were sacrificed after 24 h to assess the macroscopic/microscopic RFA injury.

RESULTS

Microscopic maximal injury depth and ablation area of EB-RFA using a 33-mm 10 W RFA electrode were significantly deeper and larger than those of EB-RFA using an 18-mm 7 W electrode (median; 2.7 vs. 2.1 mm, P = 0.004, 48.9 vs. 36.2 mm² , P = 0.016). However, there were no significant differences in microscopic ablation parameters between two different RFA target temperatures (75°C vs. 80°C). In addition, a post-RFA cholangiogram and assessment of the resected specimen at 24 h after the RFA showed no adverse events such as perforation or bleeding.

CONCLUSIONS

EB-RFA using a temperature controlled RFA catheter successfully ablates the bile duct wall without adverse events in a swine model.

Endoscopic radiofrequency ablation combined with fully covered self-expandable metal stent for inoperable periampullary carcinoma in a liver transplant patient: A case report

RATIONALE

Postliver transplant periampullary carcinoma is an extremely uncommon disease.

PATIENT CONCERNS

Cutaneous jaundice in a patient who had received a liver transplant 4 years earlier.

DIAGNOSIS

Periampullary carcinoma.

INTERVENTIONS

Radiofrequency ablation plus fully covered self-expanding metal stents (FCSEMS).

OUTCOMES

The treatment of malignant neoplasm of the ampulla of Vater is the patient by radiofrequency ablation plus FCSEMS placement was successful. No complications occurred.

LESSONS

This is the first reported case of a liver transplant patient with inoperable periampullary carcinoma successfully treated by radiofrequency ablation plus FCSEMS placement. Our experience will be useful to other surgeons in managing similar patients in the future.

Review of endoscopic radiofrequency in biliopancreatic tumours with emphasis on clinical benefits, controversies and safety

Most pancreatic cancers and extrahepatic cholangiocarcinomas are unresectable at the time of diagnosis, and even in case of a resectable cancer, for elderly or patients with coexistent comorbidities, surgery is not an option. Current treatment alternatives in these scenarios are very limited. Biliary stenting with self-expanding metal stents (SEMS) is the mainstay palliative treatment of biliary obstruction due to unresectable pancreatic cancer or cholangiocarcinoma. Nevertheless, more than 50% of SEMS become occluded after 6 mo due to tumour over- and ingrowth, leading to hospital readmissions and reinterventions that significantly impair quality of life. Regimes of chemotherapy or chemoradiotherapy also provide minimal survival benefits. Therefore, novel therapies are eagerly awaited. Radiofrequency (RF) energy causes coagulative necrosis leading to local destruction of the accessed malignant tissue and has an established role in the treatment of malignancies in several solid organs, especially liver cancers. However, pancreatic and extrahepatic biliary cancers are not easily accessed by a percutaneous route, making the procedure dangerous. Over the past five years, the development of dedicated devices compatible with endoscopic instruments has offered a minimally invasive option for RF energy delivery in biliopancreatic cancers. Emerging experience with endoscopic RF ablation (RFA) in this setting has been reported in the literature, but little is known about its feasibility, efficacy and safety. A literature review makes it clear that RFA in biliopancreatic tumours is feasible with high rates of technical success and acceptable safety profile. Although available data suggest a benefit of survival with RFA, there is not enough evidence to draw a firm conclusion about its efficacy. For this reason, prospective randomized trials comparing RFA with standard palliative treatments with quality-of-life and survival endpoints are required. Anecdotal reports have also highlighted a potential curative role of RFA in small pancreatic tumours and benign conditions, such as ductal extension of ampullomas, intrahepatic adenomas or non-tumoural biliary strictures. These newest indications also deserve further examination in larger series of studies.

Development of a Swine Benign Biliary Stricture Model Using Endoscopic Biliary Radiofrequency Ablation

The large animal model with benign biliary stricture (BBS) is essential to undergo experiment on developing new devices and endoscopic treatment. This study conducted to establish a clinically relevant porcine BBS model by means of endobiliary radiofrequency ablation (RFA). Endoscopic retrograde cholangiography (ERC) was performed on 12 swine. The animals were allocated to three groups (60, 80, and 100 W) according to the electrical power level of RFA electrode. Endobiliary RFA was applied to the common bile duct for 60 seconds using an RFA catheter that was endoscopically inserted. ERC was repeated two and four weeks, respectively, after the RFA to identify BBS. After the strictures were identified, histologic evaluations were performed. On the follow-up ERC two weeks after the procedure, a segmental bile duct stricture was observed in all animals. On microscopic examination, severe periductal fibrosis and luminal obliteration with transmural inflammation were demonstrated. Bile duct perforations occurred in two pigs (100 W, n = 1; 80 W, n = 1) but there were no major complications in the 60 W group. The application of endobiliary RFA with 60 W electrical power resulted in a safe and reproducible swine model of BBS.

Biliary tract perforation following percutaneous endobiliary radiofrequency ablation: A report of two cases

Endobiliary radiofrequency ablation (RFA) has recently been recognized as a beneficial treatment option for malignant biliary obstruction using percutaneous or endoscopic approaches. The feasibility and safety of this method has been demonstrated in clinical studies, with pain, cholangitis and asymptomatic biochemical pancreatitis reported as relatively common complications. By contrast, hepatic coma, newly diagnosed left bundle branch block and partial liver infarction have been reported as uncommon complications. Biliary tract perforation is a serious potential complication of percutaneous intraductal RFA, which may result in severe infection, peritonitis or even mortality, and which has not been previously reported in clinical research. The current study presents the first reports of biliary tract perforation in two patients with unresectable malignant biliary obstruction following percutaneous intraductal RFA. Although the patient in case 1 succumbed 12 days after RFA, the minor biliary tract perforation in case 2 was successfully treated by the deployment of a self-expanding metal stent. This study demonstrates that biliary tract perforation should be recognized as a serious potential complication of endobiliary RFA, and that metal stent deployment should be considered as a treatment option for minor biliary tract perforation.

Percutaneous Intraductal Radiofrequency Ablation Combined with Biliary Stent Placement for Nonresectable Malignant Biliary Obstruction Improves Stent Patency but not Survival

Although radiofrequency (RF) ablation has been accepted as a curative treatment modality for solid organ tumors, intraductal RF ablation for malignant biliary obstruction has not been widely described. The aim of this study was to evaluate the feasibility, safety, and efficacy (in terms of stent patency and survival) of intraductal RF ablation combined with biliary stent placement for nonresectable malignant biliary obstruction. A search of the nonresectable malignant extrahepatic biliary obstruction database (179 patients) identified 18 consecutive patients who were treated with biliary intraluminal RF ablation during percutaneous transhepatic cholangiodrainage and inner stent placement (RF ablation group) and 18 patients who underwent inner stent placement without biliary intraluminal RF ablation (control group). The patients were matched for tumor type, location of obstruction, tumor stage, and Child-Pugh class status. Primary endpoints included safety, stent patency time, and survival rates. The secondary endpoint was effectiveness of the technique. The RF ablation and control groups were closely matched in terms of age, diagnosis, presence of metastases, presence of locally advanced tumor, American Society of Anesthesiologists (ASA) grade, and chemotherapy regimen (all P > 0.05). The technical success rate for both groups was 100%. The median time of stent patency in the RF ablation and control groups were 5.8 (2.8-11.5) months and 4.5 (2.4-8.0) months, respectively (Kaplan-Meier analysis: P = 0.03). The median survival times in the RF ablation and control groups were 6.1 (4.8-15.2) months and 5.8 (4.2-16.5) months, with no significant difference according to Kaplan-Meier analysis (P = 0.45). In univariate and multivariate analyses, poorer overall survival was associated with advanced age and presence of metastases (P < 0.05). Intraductal RF ablation combined with biliary stent placement for nonresectable malignant biliary obstruction is safe and feasible and effectively increases stent patency time. However, it does not improve patient survival.

Biliary Tumor Ablation with Photodynamic Therapy and Radiofrequency Ablation

Within the past two decades, major progress has been made in biliary endoscopy both with stenting and with ablative therapy. A primary goal in patients with malignant biliary lesions who are not candidates for surgery is to provide localized and efficient necrosis of the lesions. This article summarizes the current literature on biliary tumor ablation with photodynamic therapy and radiofrequency ablation. Prognosis, treatment technique, potential complications, treatment efficacy, and controversies are discussed.

Emerging indications of endoscopic radiofrequency ablation

INTRODUCTION

Radiofrequency ablation (RFA) is a well-validated treatment of dysplastic Barrett's esophagus. Other indications of endoscopic RFA are under evaluation.

RESULTS

Four prospective studies (total 69 patients) have shown that RFA achieved complete remission of early esophageal squamous intra-epithelial neoplasia at a rate of 80%, but with a substantial risk of stricture. In the setting of gastric antral vascular ectasia, two prospective monocenter studies, and a retrospective multicenter study, (total 51 patients), suggest that RFA is efficacious in terms of reducing transfusion dependency. In the setting of chronic hemorrhagic radiation proctopathy, a prospective monocenter study and a retrospective multicenter study (total 56 patients) suggest that RFA is an efficient treatment. A retrospective comparative study (64 patients) suggests that RFA improves stents patency in malignant biliary strictures.

CONCLUSIONS

Endoscopic RFA is an upcoming treatment modality in early esophageal squamous intra-epithelial neoplasia, as well as in gastric, rectal, and biliary diseases.

Intraductal Radiofrequency Ablation Followed by Locoregional Tumor Treatments for Treating Occluded Biliary Stents in Non-Resectable Malignant Biliary Obstruction: A Single-Institution Experience

Objectives

To determine the safety and feasibility of intraductal radiofrequency ablation (RFA) followed by locoregional tumor treatments in patients with non-resectable malignant biliary obstruction and stent re-occlusion.

Methods

Fourteen patients with malignant biliary obstruction and blocked metal stents were studied retrospectively. All had intraductal RFA followed by locoregional tumor treatments and were monitored clinically and radiologically. The practicality, safety, postoperative complications, jaundice remission, stent patency and survival time were analyzed.

Results

Combination treatment was successful for all patients. There were no severe complications during RFA or local treatments. All patients had stent patency restored, with a decline in serum bilirubin. Three patients had recurrent jaundice by 195, 237 and 357 days; two patients underwent repeat intraductal RFA; and one required an internal-external biliary drain. The average stent patency time was 234 days (range 187-544 days). With a median follow-up of 384 days (range 187-544 days), six patients were alive, while eight had died. There was no mortality at 30 days. The 3, 6, 12 and 18 month survival rates were 100%, 100%, 64.3% and 42.9%, respectively.

Conclusion

Intraductal RFA followed by locoregional tumor treatments for occluded metal stents is safe and practically feasible and potential increase stent patency and survival times.

Endoscopic treatment of malignant biliary strictures

Endoscopic stenting is a widely accepted strategy for providing effective drainage in both extrahepatic and intrahepatic malignant strictures. In patients with extrahepatic malignancies, uncovered self-expanding metal stents (SEMS) provide excellent palliation. Hilar malignancies are probably best palliated by placement of uncovered SEMS although some disagreement exists among experts regarding the type and number of stents for optimal palliation. Preoperative biliary drainage (PBD) is commonly performed although a higher risk of complications and the lack of clear benefit raise questions about this practice. Certain groups of patients such as those with markedly elevated bilirubin levels, and in those in whom neoadjuvant therapy is planned, are good candidates for PBD. Considerable controversy exists regarding the optimal method as well as type of stent for PBD in patients with hilar malignancies. Novel endoscopic therapies, including photodynamic therapy and radiofrequency ablation, have emerged as potential adjuvant therapies in the management of malignant bile duct strictures but need further long-term evaluation to establish survival benefit. This review focuses on the current status of endoscopic therapies for malignant biliary obstructions.