Endobiliary radiofrequency ablation combined with bilateral metal stent placement for malignant hilar biliary obstruction

Consensus statements on endoscopic radiofrequency ablation for malignant biliary strictures

Endoscopy-guided endobiliary radiofrequency ablation has emerged as a novel treatment for malignant biliary strictures in recent years. When combined with biliary stenting and systemic chemotherapy, it can effectively postpone local tumor progression, improve patient's quality of life, and prolong their survival, which is mainly indicated for patients with inoperable extrahepatic cholangiocarcinoma and ampullary cancer. Based on the existing clinical evidence, the Digestive Endoscopology Branch of Chinese Medical Association, the Digestive Endoscopy Professional Committee, Endoscopic Physicians Branch of Chinese Medical Doctor Association, and the National Clinical Research Center for Digestive Diseases (Shanghai) organized relevant experts to discuss the indications, contraindications, technical operation specifications, and prevention and treatment of the complications during endoscopy-guided endobiliary radiofrequency ablation. Consensus statements were established, trying to provide references for standard treatment of malignant biliary tumors in clinical practice.

Endoscopic Treatment of Malignant Hilar Biliary Obstruction

Stent implantation is an effective approach for palliative treatment of Bismuth-Corlette type III-IV malignant hilar biliary obstructions (MHBOs). In this article, we reviewed the currently used access methods for biliary stent placement (percutaneous transhepatic biliary drainage, endoscopic biliary drainage, endosonography guided biliary drainage), the available stent types (plastic stent, self-expanding metallic stent, full cover self-expanding metallic stent, radioactive self-expanding metallic stent), major approaches (unilateral, bilateral) and deployment methods (stent-in-stent, stent-by-stent). Finally, this review gives an outlook on perspectives of development in stenting and other palliative methods in MHBO.

Long-term disease control by endobiliary radiofrequency ablation in localized extrahepatic cholangiocarcinoma: a first case report

An 84-year-old woman with cerebrovascular disease, dementia, and chronic kidney disease developed jaundice because of localized extrahepatic cholangiocarcinoma (eCCA) at the lower bile duct. Aggressive treatment, including surgery and chemotherapy, was difficult because of the underlying disease; therefore, only metal stent placement with endobiliary radiofrequency ablation (RFA) was performed. Subsequently, six additional RFA sessions were performed 12, 16, 24, 27, 33, and 36 months after the initial RFA using the same settings as the first RFA session. All these procedures were performed for tumor ingrowth. Computed tomography performed 42 months after the initial procedure revealed no stent with stricture resolution and no other metastatic lesion. Thereafter, no recurrence or adverse events have been observed with persisting stent-free status until the reporting of this study (72 months after the initial procedure). This is the first report of a stent-free status and long-term survival in a patient with localized eCCA that was achieved using only endobiliary RFA without any other anti-tumor treatment. Although several problems and issues associated with endobiliary RFA remain unelucidated, it may be a useful therapeutic option for early and localized eCCA in poor surgical candidates.

Endoscopic intraductal radiofrequency ablation for extrahepatic cholangiocarcinoma: An update (2023)

Recently, endoscopic intraductal radiofrequency ablation (ID-RFA) has attracted attention as a local treatment method for malignant biliary obstruction (MBO). ID-RFA causes coagulative necrosis of the tumor tissue in the stricture and induces exfoliation. Its effects are expected to extend the patency period of biliary stents and prolong the survival period. Evidence for extrahepatic cholangiocarcinoma (eCCA) is gradually accumulating, and some reports show significant therapeutic effects in eCCA patients without distant metastasis. However, it is still far from an established treatment technique, and many unsolved problems remain. Therefore, when performing ID-RFA in clinical practice, it is necessary to understand and grasp the current evidence well and to operate appropriately for the true benefit of the patients. This paper reviews the current status, issues, and prospects of endoscopic ID-RFA for MBO, especially for eCCA.

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.

Double bare metal stent deployment combined with intraductal radiofrequency ablation for malignant distal biliary obstruction: a prospective pilot study

Although uncovered self-expandable metal stents (SEMSs) possess certain advantages such as averting cystic duct obstruction and stent migration, they are susceptible to ingrowth occlusion. The combination of the double bare stent (DBS) and endobiliary radiofrequency ablation (RFA) may reduce ingrowth. Hence, this study aimed to examine the utility of this method for the treatment of unresectable malignant distal biliary obstruction (MDBO). This prospective, single-center, pilot study enrolled 51 patients who met the eligibility criteria between February 2020 and January 2022. The study outcomes included technical success, clinical success, recurrent biliary obstruction (RBO), and other adverse events (AE) besides RBO associated with DBS placement with RFA for MDBO. The technical success rate was 98.0% (50/51). Clinical success was achieved in all patients in whom technical success was achieved. The rates of early and late AEs were 5.9% (3/51) and 8.0% (4/50), respectively. The incidence rate of RBO was 38.0% (19/50). Sludge occlusion, ingrowth occlusion, and overgrowth occlusion occurred in 26.0% (13/50), 8.0% (4/50), and 2.0% (1/50) of patients, respectively (the main cause of RBO was undeterminable in 1 patient). The median time to RBO was 241 days. DBS with RFA showed good technical feasibility, good long-term outcomes, acceptable AE rates, and most importantly, a low ingrowth occlusion rate when employed for the treatment of MDBO.

Endoscopic radiofrequency ablation for ingrowth occlusion after bilateral metal stent placement for malignant hilar biliary obstruction: a prospective pilot study

BACKGROUND AND AIMS

Endoscopic biliary radiofrequency ablation (RFA) may be an option for the treatment of ingrowth occlusion after self-expandable metal stent (SEMS) deployment; however, its utility remains uncertain. This study aimed to examine the feasibility of RFA for the palliation of ingrowth after bilateral SEMS placement in patients with malignant hilar biliary obstruction.

METHODS

This prospective, single-center, pilot study enrolled 30 patients who met the eligibility criteria between April 2020 and March 2022. Study outcomes were technical success, clinical success, recurrent biliary obstruction (RBO), and adverse events (AEs) besides RBO associated with RFA for ingrowth occlusion. Furthermore, factors predictive of clinical success were evaluated.

RESULTS

Technical and clinical success rates were 93.3% (28/30) and 71.4% (20/28), respectively. The rates of early and late AEs were 6.7% (2/30) and 10.0% (2/20), respectively. The incidence rate of RBO after RFA was 45.0% (9/20), and the median time to RBO was 163 days. Multivariate analysis of the factors affecting clinical success revealed a positive association between the recanalization diameter on the ingrown part within the SEMS (odds ratio, 1.13; 95% confidence interval, 1.01-1.26; P = .038). The calculated optimal cutoff for the ratio of the recanalization diameter to the SEMS diameter for predicting clinical success was 51.1%.

CONCLUSIONS

Endoscopic biliary RFA elicited promising results, with good long-term stent patency and without the requirement of any additional stent placement, for the palliation of ingrowth occlusion after bilateral SEMS placement. However, the clinical success rate was insufficient, necessitating improvements in the future. (Clinical trial registration number: UMIN000040154.).

Endoscopic biliary ethanol ablation using a novel multi-hole balloon catheter: In vivo feasibility study in a swine model

BACKGROUND

Minimally invasive local treatment could be a good option for the treatment of extrahepatic cholangiocarcinoma (eCCA). This study aimed to evaluate the feasibility of a novel local treatment method, endoscopic biliary ethanol ablation (EA), in vivo using a swine model.

METHODS

This study utilized a prototype of the newly developed multi-hole balloon catheter. The swine bile duct was ablated using this balloon via the same approach as the conventional endoscopic retrograde cholangiography procedure. The study outcomes included technical success, clinical success, and adverse events associated with endoscopic biliary EA.

RESULTS

Fourteen miniature pigs underwent endoscopic biliary EA. Technical success was achieved for all endoscopic EA procedures without any hindrance. All pigs were reared and followed up for a median 35-day period after the procedure. No change was observed in the bile duct wall in one case, in which sufficient contact was not achieved between the balloon and bile duct wall. Except for this case, stricture formation occurred at the site of ablation, where the epithelium was sloughed and necrosis with denaturation replaced the granulation tissue and fibrotic changes. The median length and depth of the ablation area were 17.05 and 2.21 mm, respectively. No adverse events were observed, except for the formation of bile duct strictures and sequelae associated with strictures.

CONCLUSIONS

This preliminary study was the first to report endoscopic biliary EA using a novel multi-hole balloon catheter, which demonstrated technical feasibility and potential for the treatment for eCCA.

Endobiliary and Pancreatic Radiofrequency Ablations

Radio frequency ablation (RFA) involves use of thermal energy to perform ablation of tissues. It has a wide range of application in gastrointestinal tract. Over the last few years, several studies have reported successful and safe application in the biliary and pancreatic tissues. It is particularly beneficial in patients with biliary malignancies in whom it has shown to improve survival. Additionally, it can be applied in occluded metal stents secondary to tumor ingrowth to prolong the patency of stents. In pancreas, RFA can successfully ablate cystic lesions and neuroendocrine tumors. It has also been applied in unresectable pancreatic cancers. This review discusses the application of endobiliary and pancreatic RFAs.

The usefulness of endobiliary radiofrequency ablation before metal stent placement in unresectable malignant hilar obstruction

BACKGROUND AND AIM

EB-RFA with self-expandable metal stent (SEMS) may improve the stent patency and patient survival in malignant extrahepatic biliary obstruction. However, there are few studies on the role of EB-RFA for malignant hilar obstruction (MHO). This study aimed to assess the feasibility, efficacy, and safety of EB-RFA for MHO.

METHODS

We retrospectively compared the stent patency and survival among 79 consecutive patients with MHO who underwent bilateral uncovered SEMS placement without and with EB-RFA between April 2016 and January 2020.

RESULTS

Fifty-one patients (64.6%) underwent SEMS placement alone (stent alone group), whereas 28 (35.4%) underwent SEMS placement after EB-RFA (RFA-stent group). All procedures were successful (100%). During follow-up, stent occlusion occurred in 59 patients (74.7%), of which 40 (78.4%) and 19 (67.9%) were in the stent alone and RFA-stent groups, respectively. There was no difference in stent patency (192 ± 39.2 days vs 140 ± 53.7 days, P = 0.41) and survival (311 ± 24.7 days vs 311 ± 46.9 days, P = 0.73) between the stent alone and RFA-stent groups. Multivariate cox analysis showed a hazard ratio (HR) of 2.892 (1.579-5.294, P = 0.001) for stent occlusion in patients who did not receive chemotherapy. EB-RFA had no significant effect on stent occlusion (HR, 1.150, 0.644-2.053, P = 0.636).

CONCLUSIONS

SEMS placement after EB-RFA in MHO was not associated with improvement in the stent patency or patient survival. Further prospective randomized studies are necessary to establish the effectiveness of EB-RFA with stents in MHO.

Endobiliary Radiofrequency Ablation Using a Short-Type Balloon Enteroscope in Patients with Surgically Altered Anatomy

BACKGROUND

Endoscopic radiofrequency ablation (RFA) is expected to prolong stent patency for malignant biliary obstruction (MBO). However, its feasibility when used in conjunction with a balloon enteroscope (BE) in patients with surgically altered anatomy (SAA) remains unknown.

AIMS

This study aimed to investigate the feasibility of RFA combined with metal stent insertion under BE guidance for MBO in patients with SAA.

METHODS

Thirty-seven patients who underwent treatment between October 2016 and January 2021 and met the eligibility criteria were investigated retrospectively. Study outcomes included technical and clinical success, recurrent biliary obstruction (RBO), and other adverse events besides RBO associated with RFA with metal stent placement using BE.

RESULTS

Technical and clinical success rates were 100% (37/37) each. The rates of early and late adverse events were 8.1% (3/37) and 8.1% (3/37), respectively. RBO occurred in 32.4% (12/37) of the patients, and the median time to RBO was 296 days. The cause of RBO was ingrowth in eight patients, overgrowth in three patients, and indeterminate in one patient. All reinterventions for RBO were successful using the BE approach; all ingrowths, except one, were recanalized using additional RFA without additional stent placement. The frequency of reintervention-related adverse events was 9.1% (1/11). The median time to RBO after reintervention was 166 days.

CONCLUSIONS

This study demonstrated the technical safety and feasibility as well as good long-term outcomes of endobiliary RFA combined with metal stent placement under BE guidance. This approach may be a useful option for treating MBO in patients with SAA.

Role of ERCP in Malignant Hilar Biliary Obstruction

Malignant hilar biliary obstruction (MHO), an aggressive perihilar biliary obstruction caused by cholangiocarcinoma, gallbladder cancer, or other metastatic malignancies, has a poor prognosis. Surgical resection is the only curative treatment method for biliary malignancies. However, most of the patients with MHO cannot undergo surgeries on presentation because of an advanced inoperable state or a poor performance state due to old age or comorbid diseases. Therefore, palliative biliary drainage is mandatory to improve symptomatic jaundice and quality of life. Among drainage methods, endoscopic biliary drainage is the current standard for the palliation of unresectable advanced MHO. The development of stents and various accessories and advances in endoscopic techniques including endoscopic ultrasonography have facilitated primary endoscopic intervention in difficult high-grade hilar strictures. However, some issues are still under debate, such as palliation methods, appropriate stents, the number of stents, deployment methods, and additional local ablation therapies. Therefore, this review presents currently optimal endoscopic palliation methods for advanced MHO based on the reported literature.

Endobiliary Radiofrequency Ablation Combined with Gemcitabine and Cisplatin in Patients with Unresectable Extrahepatic Cholangiocarcinoma

Background: Endobiliary radiofrequency ablation (RFA) is a promising treatment modality for patients with extrahepatic cholangiocarcinoma (eCCA). However, no study has investigated the combined use of endobiliary RFA and gemcitabine plus cisplatin (GC) chemotherapy. This study aimed to examine the feasibility and efficacy of endobiliary RFA with GC therapy for patients with unresectable eCCA. Methods: The study outcomes included overall survival (OS), progression-free survival (PFS), time to recurrent biliary obstruction (RBO), and adverse events associated with the treatment. These parameters were retrospectively compared between 25 patients who underwent RFA with self-expandable metal stent (SEMS) placement followed by GC therapy (with-RFA group) and a control cohort of 25 patients who underwent SEMS placement alone and GC therapy (without-RFA group). Results: The median time to RBO was significantly longer in the with-RFA group (10.7 versus 5.2 months, p = 0.048). The median OS was significantly higher in patients with locally advanced tumors in the with-RFA group (23.1 versus 16.6 months, p = 0.032), but did not differ significantly in patients with metastasis (11.4 versus 8.5 months, p = 0.180). Similarly, the median PFS was significantly higher in the with-RFA group in patients with locally advanced disease (10.1 versus 7.3 months, p = 0.015), while there was no significant difference in patients with metastasis (5.4 versus 4.4 months, p = 0.529). The rates of various toxicities did not differ significantly between the groups. Conclusions: Endobiliary RFA prolonged the patency period of uncovered SEMS combined with GC therapy in patients with eCCA. Although RFA also yielded survival benefits, its effect was restricted to locally advanced tumors.

Updated evidence on the clinical impact of endoscopic radiofrequency ablation in the treatment of malignant biliary obstruction

Endoscopic biliary radiofrequency ablation (RFA) was recently developed as a novel adjunctive procedure and a promising therapeutic option in patients with malignant biliary obstruction (MBO). RFA can achieve local tumor control, resulting in improved biliary stent patency and a potential survival benefit. However, the efficacy of biliary RFA remains controversial, and previous studies have shown conflicting results. At present, extrahepatic cholangiocarcinoma is considered the condition most effectively treated by biliary RFA, but there is limited research even on this point. Further, limitations of RFA associated with the devices used during the procedure are an important subject of discussion. In addition to further well-designed clinical trials, development of innovative devices is warranted to investigate and conclusively establish the usefulness of biliary RFA. In this review we summarize the updated evidence regarding the use of endoscopic biliary RFA for MBO and discuss issues that should be addressed in future studies.

Efficacy and safety of temperature-controlled intraductal radiofrequency ablation in advanced malignant hilar biliary obstruction: A pilot multicenter randomized comparative trial

PURPOSE

We aimed to evaluate the efficacy and safety of temperature-controlled intraductal radiofrequency ablation (ID-RFA) for advanced malignant hilar biliary obstruction (MHBO).

METHODS

Patients were randomly assigned to RFA group (ID-RFA and bilateral plastic stent [PS]) or non-RFA group (bilateral PS) at a 1:1 ratio. Exchange to self-expanding metal stent (SEMS) was performed after 3 months or when premature PS occlusion occurred. Total event-free stent patency, overall survival (OS), and adverse events (AEs) were analyzed.

RESULTS

A total of 30 patients from three hospitals were enrolled. Stent patency and OS did not differ between the two groups (178 days vs 122 days, P = .154; 230 days vs 144 days, P = .643; respectively). In patients with each stricture length ≥11 mm on both sides, stent patency was longer in the RFA group than in the non-RFA group (175 days vs 121 days, P = .028). More patients received elective exchange to SEMS without PS occlusion in the RFA group than in the non-RFA group (69.2% vs 23.1%, P = .018). AE rates did not differ between the two groups.

CONCLUSIONS

Temperature-controlled ID-RFA for advanced MHBO was safe and feasible. It could prevent premature PS occlusion within 3 months.

Tips and tricks for the diagnosis and management of biliary stenosis-state of the art review

Biliary stenosis may represent a diagnostic and therapeutic challenge resulting in a delay in diagnosis and initiation of therapy due to the frequent difficulty in distinguishing a benign from a malignant stricture. In such cases, the diagnostic flowchart includes the sequential execution of imaging techniques, such as magnetic resonance, magnetic resonance cholangiopancreatography, and endoscopic ultrasound, while endoscopic retrograde cholangiopancreatography is performed to collect tissue for histopathological/cytological diagnosis or to treat the stenosis by insertion of stent. The execution of percutaneous transhepatic drainage with subsequent biopsy has been shown to increase the possibility of tissue diagnosis after failure of the above techniques. Although the diagnostic yield of histopathology and imaging has increased with improvements in endoscopic ultrasound and peroral cholangioscopy, differential diagnosis between malignant and benign stenosis may not be easy in some patients, and strictures are classified as indeterminate. In these cases, a multidisciplinary workup including biochemical marker assays and advanced technologies available may speed up a diagnosis of malignancy or avoid unnecessary surgery in the event of a benign stricture. Here, we review recent advancements in the diagnosis and management of biliary strictures and describe tips and tricks to increase diagnostic yields in clinical routine.

Endoscopic radiofrequency ablation for malignant biliary obstruction

Cholangiocarcinoma and pancreatic cancer are the most common causes of malignant biliary obstruction. The majority of patients are diagnosed at a late stage when surgical resection is rarely possible. In these cases, palliative chemotherapy and radiotherapy provide only limited benefit and are associated with poor survival. Radiofrequency ablation (RFA) is a procedure for locoregional control of tumours, whereby a high-frequency alternating current turned into thermal energy causes coagulative necrosis of the tissue surrounding the catheter. The subsequent release of debris and tumour antigens by necrotic cells can stimulate local and systemic immunity. The development of endoluminal RFA catheters has led to the emergence of endoscopically delivered RFA, a treatment mainly used for malignant biliary strictures to prolong survival and/or stent patency. Other indications include recanalisation of occluded biliary stents and treatment of intraductal ampullary adenoma or benign biliary strictures. This article presents a comprehensive review of endobiliary RFA, mainly focusing on its use in patients with malignant biliary obstruction. The available data suggest that biliary RFA may be a promising modality, having positive impacts on survival and stent patency and boasting a reasonable safety profile. However, further studies with better characterised and stratified patient populations are needed before the method becomes accepted within routine clinical practice.

[A Recent Update on Endoscopic Drainage of Advanced Malignant Hilar Obstruction]

Malignant hilar obstruction (MHO) is considered an aggressive perihilar obstruction caused by cholangiocarcinoma, gallbladder cancer, or metastatic malignancies and has a poor prognosis. Although surgical resection is the only curative treatment method, the majority of patients with MHO do not undergo surgery due to an advanced inoperable state at presentation. Currently, effective biliary drainage provides the necessary palliation for symptomatic improvement. Among the drainage methods, percutaneous access may be preferred, especially for advanced MHO because of the technical difficulty involved with other techniques. Recently, primary endoscopic palliation using plastic or metal stents has been shown to have higher technical feasibility and clinical success without increasing adverse events even in patients with high-degree MHO. The development of various accessories, endoscopic ultrasonography, and advances in techniques have facilitated primary endoscopic intervention. However, some aspects continue to be debated such as the palliation methods, appropriate stents, the number of stents, the deployment methods, and additional local ablation therapies. Therefore, this review discusses the current optimal endoscopic treatment methods for advanced MHO based on reported literature.

Stent placement combined with intraluminal radiofrequency ablation and hepatic arterial infusion chemotherapy for advanced biliary tract cancers with biliary obstruction: a multicentre, retrospective, controlled study

OBJECTIVE

To evaluate the efficacy and safety of stent placement combined with intraluminal radiofrequency ablation (intra-RFA) and hepatic arterial infusion chemotherapy (HAIC) for patients with advanced biliary tract cancers (Ad-BTCs) and biliary obstruction (BO).

METHODS

We retrospectively reviewed data for patients with Ad-BTCs and BO who underwent stent placement with or without intra-RFA and HAIC in three centres between November 2013 and November 2018. The stent patency time (SPT), overall survival (OS), and adverse events (AEs) were analysed.

RESULTS

Of the 135 enrolled patients, 64 underwent stent placement combined with intra-RFA and HAIC, while 71 underwent only stent placement. The median SPT was significantly longer in the combination group (8.2 months, 95% confidence interval [CI]: 7.1-9.3) than in the control group (4.3 months, 95% CI: 3.6-5.0; p < 0.001). A similar result was observed for OS (combination: 13.2 months, 95% CI: 11.1-16.5; control: 8.5 months, 95% CI: 7.6-9.6; p < 0.001). The incidence of AEs related to biliary tract operation was not significantly different between the two groups (p > 0.05). The most common AE and serious AE related to HAIC were alanine aminotransferase elevation (24/64; 37.5%) and thrombocytopenia (8/64; 12.5%), respectively. All AEs were tolerable, and there was no death from AEs.

CONCLUSIONS

Stent placement combined with intra-RFA and HAIC may be a safe, potential treatment strategy for patients with Ad-BTCs and BO.

KEY POINTS

• Advanced biliary cancers (Ad-BTCs) with biliary obstruction (BO) can rapidly result in liver failure and cachexia with an extremely poor prognosis. • Stent placement combined with intraluminal radiofrequency ablation and hepatic arterial infusion chemotherapy may be safe and effective for patients with Ad-BTCs and BO. • The long-term efficacy and safety of the combined treatment is promising.

Endoscopic Ultrasound-Guided Antegrade Radiofrequency Ablation and Metal Stenting With Hepaticoenterostomy for Malignant Biliary Obstruction: A Prospective Preliminary Study

Endobiliary radiofrequency ablation (RFA) for malignant biliary obstruction is a promising option for improving biliary stent patency, but its efficacy and safety with endoscopic ultrasound (EUS)-guided biliary drainage are uncertain. We examined the feasibility of EUS-guided hepaticoenterostomy with antegrade stenting (EUS-HEAS) and RFA in patients with unresectable malignant biliary obstruction.

Feasibility of balloon-based endobiliary radiofrequency ablation under cholangioscopy guidance in a swine model

Although endobiliary radiofrequency ablation (RFA) has demonstrated considerable potential for the treatment of biliary strictures, conventional catheter RFA has several limitations. This study aimed to evaluate the feasibility of a novel cholangioscopy (CS)-guided balloon-based RFA procedure in vivo using a swine model. CS-guided balloon-RFA was performed under endoscopic retrograde cholangiography guidance at target temperatures of 60 ℃ or 70 ℃, which were maintained for 60 s. We evaluated the technical feasibility, adverse events, and histological effects associated with the procedure. Twelve sites were ablated in seven miniature pigs. The CS-guided balloon-RFA procedure was technically successful in all cases without any hindrance. Mucosal changes could be detected during RFA, and the ablation area was identified on CS. Necropsy was performed in four pigs on the same day as the procedure: the tissue samples showed coagulative necrosis, and the entire internal circumference of the bile duct was uniformly ablated. The mean lengths of the ablation area in the samples ablated at 60 °C and 70 °C were 20.64 and 22.18 mm, respectively, while the mean depths were 3.46 and 5.07 mm, respectively. The other three pigs were reared and euthanized and autopsied 35 days after the procedure. The site to be ablated had replaced the granulation tissue and fibrotic changes. No adverse events were observed in any case. CS-guided balloon-RFA appears to be a promising option for treating biliary strictures. This preliminary study could pave the way for the evaluation of this procedure in future human clinical trials.

Evaluating the tissue effects of balloon-based endobiliary radiofrequency ablation in porcine bile ducts

BACKGROUND

We developed a novel balloon-based endobiliary radiofrequency ablation (RFA) system to overcome the limitations of conventional RFA in treating malignant biliary strictures. This study aimed to evaluate the histological effects of balloon-RFA in porcine bile ducts.

METHODS

Balloon-RFA of intrahepatic bile ducts from freshly resected porcine livers was performed for 60 s at 50, 60 and 70 °C. The specimens were subsequently sectioned for histological analysis and the slides were digitally scanned. Pseudo-coloring was applied based on the intensity of the ablation effect, and the area and estimated volume of ablation were measured.

RESULTS

All samples showed epithelial sloughing and coagulative necrosis, and the entire internal circumference of the bile duct was evenly ablated. Complete transmural necrosis and involvement beyond the wall were found in 0% of samples ablated at 50 °C, in 33% at 60 °C and 100% at 70 °C. The mean depth and estimated volume of the ablation areas were 1.29 mm and 353.84 mm³, 1.44 mm, and 505.54 mm³ and 1.81 mm and 702.52 mm³ at 50, 60 and 70 °C, respectively.

CONCLUSIONS

Balloon-RFA leads to sloughing of the mucosa and coagulative necrosis. Ablation depth and volume increased in proportion to target temperature.

Effect of endoscopic radiofrequency ablation on the survival of patients with inoperable malignant biliary strictures: A large cohort study

BACKGROUND AND AIMS

Endoscopic radiofrequency ablation (RFA) is an emerging technique for the palliation of inoperable malignant biliary strictures (MBSs). We aimed to systemically investigate the long-term outcome of RFA in a large cohort of patients.

METHODS

We recruited 883 patients with various MBSs who underwent endoscopic interventions at two large-volume centers; 124 patients underwent RFA and stenting, whereas 759 underwent stenting alone. To overcome selection bias, we performed 1:4 propensity score matching (PSM). The main outcome was overall survival (OS).

RESULTS

Following PSM, patients in the RFA group showed significantly longer OS (9.5 months; 95% CI: 7.7-11.3 months) than those in the stenting alone group (6.1 months; 95% CI: 5.6-6.6 months; P < .001). In stratified analyses, the improved OS was only demonstrated in the subgroup of extrahepatic cholangiocarcinoma (11.3 months 95% CI: 10.2-12.4 vs 6.9 months 95% CI: 6.0-7.8; P < .001), but not in the subgroups of gallbladder cancer, hepatocellular carcinoma, intrahepatic cholangiocarcinoma, pancreatic cancer, and other metastatic cancers (all P > .05). The survival benefits were noted only in the patients with non-metastatic cholangiocarcinoma (11.5 vs 7.4 months, P < .001).

CONCLUSIONS

The survival benefits of endoscopic RFA appear to be limited to patients with extrahepatic cholangiocarcinoma without distant metastasis.

Unilateral versus Bilateral Endoscopic Nasobiliary Drainage and Subsequent Metal Stent Placement for Unresectable Malignant Hilar Obstruction: A Multicenter Randomized Controlled Trial

(1) Background: Endoscopic management of hilar biliary obstruction is still challenging. Compared with unilateral drainage, bilateral drainage could preserve larger functional liver volume and potentially improve clinical outcomes. To evaluate the effectiveness of bilateral drainage, we conducted this multicenter randomized controlled study. (2) Methods: Patients with unresectable malignant hilar biliary obstruction were assigned to unilateral or bilateral group. At first, patients underwent endoscopic nasobiliary drainage (ENBD), and subsequently underwent self-expandable metallic stent (SEMS) deployment. Primary outcomes were the functional success rate of ENBD and time to recurrent biliary obstruction (TRBO) after SEMS deployment. (3) Results: During the study period, 38 and 39 patients were enrolled in the unilateral and bilateral groups. The functional success rate was similar in the uni- and bi-ENBD group (57% vs. 56%; p = 0.99), but the rate of additional drainage was higher in uni-ENBD group. Although TRBO and overall survival time after SEMS deployment were not different between the groups (p = 0.11 and 0.78, respectively), the incidence of early adverse events tended to be higher in the bi-SEMS group (5.3% vs. 28%; p = 0.11). (4) Conclusions: Our study failed to demonstrate the superiority of bilateral over unilateral biliary drainage in terms of functional success rate and TRBO.

Advances in the endoscopic management of malignant biliary obstruction

Biliary obstruction is common in pancreatobiliary malignancies and has a negative impact on the patient’s quality of life, postoperative complications, and survival rates. Particularly in the last decade, there has been enormous progress regarding the diagnostic and therapeutic options in patients with malignant biliary obstruction. Endoscopy has given a new insight in this direction and novel techniques have been developed for the better characterization and treatment of malignant strictures. We herein summarize the available data on the different endoscopic techniques, and clarify their role in the diagnosis and treatment of malignant biliary obstructive disease. Finally, we propose an algorithm that can facilitate management decisions in these patients.