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

Management of intrahepatic and perihilar cholangiocarcinomas: Guidelines of the French Association for the Study of the Liver (AFEF)

Intrahepatic cholangiocarcinoma (iCCA) is the second most common malignant primary liver cancer. iCCA may develop on an underlying chronic liver disease and its incidence is growing in relation with the epidemics of obesity and metabolic diseases. In contrast, perihilar cholangiocarcinoma (pCCA) may follow a history of chronic inflammatory diseases of the biliary tract. The initial management of CCAs is often complex and requires multidisciplinary expertise. The French Association for the Study of the Liver wished to organize guidelines in order to summarize the best evidence available about several key points in iCCA and pCCA. These guidelines have been elaborated based on the level of evidence available in the literature and each recommendation has been analysed, discussed and voted by the panel of experts. They describe the epidemiology of CCA as well as how patients with iCCA or pCCA should be managed from diagnosis to treatment. The most recent developments of personalized medicine and use of targeted therapies are also highlighted.

Impact of temperature-controlled endobiliary radiofrequency ablation for inoperable hilar cholangiocarcinoma: A propensity score-matched analysis

Background and study aims Endobiliary radiofrequency ablation (RFA) can be an effective palliative treatment, but few studies have evaluated its outcomes for malignant obstruction in the hilar bile duct, which has a thin wall and complex duct-vascular contacts. We evaluated the efficacy and safety of temperature-controlled endobiliary RFA, which can reduce the risk of unintentional thermal injury by maintaining the temperature of the ablation segment, in the treatment of inoperable hilar cholangiocarcinoma (CCA). Patients and methods After propensity score matching, 64 patients with inoperable hilar CCA were categorized to the RFA + stent group (endobiliary RFA with stenting; n=32) or stent-only group (stenting only; n=32). The evaluated outcomes were the median time to recurrent biliary obstruction (RBO), overall survival (OS), and adverse events (AEs). Results Technical success was achieved in all patients. The clinical success rate was 93.8% in the RFA + stent group and 87.5% in the stent-only group ( P =0.672). The median time to RBO was 242 days in the RFA + stent group and 168 days in the stent-only group ( P =0.031). The median OS showed a non-significant tendency to be higher in the RFA + stent group (337 versus 296 days; P =0.260). Overall AE rates were comparable between the two groups (12.5% vs 9.4%, P =1.000). Conclusions Temperature-controlled endobiliary RFA resulted in favorable stent patency without increasing the rate of AEs but it did not significantly increase OS in patients with inoperable hilar CCA (Clinical trial registration number: KCT0008576).

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.

Current interventional options for palliative care for patients with advanced-stage cholangiocarcinoma

Primary biliary tract tumors are malignancies that originate in the liver, bile ducts, or gallbladder. These tumors often present with jaundice of unknown etiology, leading to delayed diagnosis and advanced disease. Currently, several palliative treatment options are available for primary biliary tract tumors. They include percutaneous transhepatic biliary drainage (PTBD), biliary stenting, and surgical interventions such as biliary diversion. Systemic therapy is also commonly used for the palliative treatment of primary biliary tract tumors. It involves the administration of chemotherapy drugs, such as gemcitabine and cisplatin, which have shown promising results in improving overall survival in patients with advanced biliary tract tumors. PTBD is another palliative treatment option for patients with unresectable or inoperable malignant biliary obstruction. Biliary stenting can also be used as a palliative treatment option to alleviate symptoms in patients with unresectable or inoperable malignant biliary obstruction. Surgical interventions, such as biliary diversion, have traditionally been used as palliative options for primary biliary tract tumors. However, biliary diversion only provides temporary relief and does not remove the tumor. Primary biliary tract tumors often present in advanced stages, making palliative treatment the primary option for improving the quality of life of patients.

Intraductal radiofrequency ablation plus biliary stent versus stent alone for malignant biliary obstruction: a systematic review and meta-analysis

Background and study aims Recurrent biliary stent occlusion and tumor ingrowth remain a major concern among patients with malignant biliary obstruction (MBO) with significant impact on patient morbidity and survival. Intraductal radiofrequency ablation (RFA) has emerged as a promising treatment that seeks to extend stent patency. This study aimed to evaluate the impact of RFA on overall survival (OS) and stent patency among patients with unresectable MBO. Methods A comprehensive search of electronic databases was performed for randomized controlled trials (RCTs) comparing RFA plus biliary stent (RFA+S) versus biliary stent alone (S-alone). Outcomes assessed included overall survival, stent patency, and adverse events (AEs) with mean difference (MD) calculated from pooled proportions. Subgroup analyses were performed for hilar strictures and cholangiocarcinoma (CCA). Results Six RCTs (n=439 patients) were included and demonstrated improved survival among patients who received RFA+S (MD 85.80 days; 95% confidence interval [CI] 35.02-136.58; I 2 =97%; P <0.0009). The pooled MD for total stent patency was 22.25 days (95% CI 17.38-61.87; I 2 =97%; P =0.27). There was no difference in AEs between RFA+S vs S-alone ( P >0.05). On subgroup analyses, RFA+S was associated with improved stent patency (MD 76.73 days; 95% CI 50.11-103.34; I 2 =67%; P <0.01) and OS (MD 83.14 (95% CI 29.52-136.77; I 2 =97%; P <0.01] for CCA. For hilar strictures, stent patency was improved among patients with RFA+S [MD 83.71 days (95% CI 24.85-142.56; I 2 =84%; P <0.01]. Conclusions RFA+S improved OS in the treatment of MBO when compared with S-alone. Moreover, the RFA therapy prolonged stent patency in hilar strictures and CCA, with similar rates of AEs.

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.

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.

Endoluminal radiofrequency ablation in patients with malignant biliary obstruction: a randomised trial

BACKGROUND

Endoluminal radiofrequency ablation (RFA) has been promoted as palliative treatment for patients with cholangiocarcinoma (CCA) and pancreatic ductal adenocarcinoma (PDAC) in order to improve biliary drainage and eventually prolong survival. No high level evidence is, however, available on this technique.

DESIGN

In this randomised controlled study, we compared endoluminal RFA plus stenting with stenting alone (control group) in patients with malignant biliary obstruction; metal stents were primarily placed. Primary outcome was overall survival; secondary outcomes were stent patency, quality of life and adverse events. In a superiority design, survival was assumed to be doubled by RFA as compared with 6.4 months in the control group (n=280).

RESULTS

A total of 161 patients (male:female 90:71, mean age 71±9 years) were randomised before recruitment was terminated for futility after an interim analysis. Eighty-five patients had CCA (73 hilar, 12 distal) and 76 had pancreatic cancer. There was no difference in survival in both subgroups: for patients with CCA, median survival was 10.5 months (95% CI 6.7 to 18.3) in the RFA group vs 10.6 months (95% CI 9.0 to 24.8), p=0.58)) in the control group. In the subgroup with pancreatic cancer, median survival was 6.4 months (95% CI 4.3 to 9.7) for the RFA vs 7.7 months (95% CI 5.6 to 11.3), p=0.73) for the control group. No benefit was seen in the RFA group with regard to stent patency (at 12 months 40% vs 36% in CCA and 66% vs 65% in PDAC), and quality of life was unchanged by either treatment and comparable between the groups. Adverse events occurred in seven patients in each groups.

CONCLUSION

A combination of endoluminal RFA and stenting was not superior to stenting alone in prolonging survival or improving stent patency in patients with malignant biliary obstruction.

TRIAL REGISTRATION NUMBER

NCT03166436.

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.

Effect of radiofrequency ablation in addition to biliary stent on overall survival and stent patency in malignant biliary obstruction: an updated systematic review and meta-analysis

OBJECTIVES

Radiofrequency ablation (RFA) is used in addition to stent placement to manage extrahepatic malignant biliary obstruction. We aimed to study the effect of RFA on overall survival (OS) and stent patency in malignant biliary obstruction.

METHODS

A comprehensive literature search was performed from inception to May 2022 for all studies measuring the effect of RFA plus stents compared to stents placement only on OS and stent patency in patients with malignant biliary obstruction. We measured differences in OS, stent patency, and odds of adverse events. A random effect model was used to pool data for stent patency, OS, and adverse event.

RESULTS

A total of 17 studies (14 observational and 3 RCT) containing 1766 patients were included in the analysis. The weighted pooled mean survival difference was 58.5 days [95% confidence interval (CI): 32.6-84.4, I2 = 71%] in favor of the RFA treatment group. The weighted mean difference in stent patency was better in the RFA plus stent group by 45.3 days (95% CI: 30.1-60.5, I2 = 16.4%) compared to stent only group. The pooled odds of adverse events were the same in both groups [odds ratio (OR) 1.52, 95% CI: 0.96-2.43, I2 = 59%], and no serious adverse event was seen in either group, or no death reported secondary to RFA procedure. No difference in stent patency based on procedure type, including percutaneous transhepatic cholangiography versus endoscopic retrograde cholangiopancreatography (P = 0.06), and an underline cause of bile duct obstruction was found (P = 0.261).

CONCLUSION

RFA treatment, in addition to stent placement in malignant biliary obstruction, potentially improves OS and stent patency duration.

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.

In-stent radiofrequency ablation with uncovered metal stent placement for tumor ingrowth/overgrowth causing self-expandable metal stent occlusion in distal malignant biliary obstruction: multicenter propensity score-matched study

BACKGROUND AND AIMS

In patients with unresectable malignant biliary obstruction (MBO), endoscopic drainage with a self-expandable metal stent (SEMS) is a well-established treatment, but stent patency is limited. This study aimed to evaluate the efficacy of in-stent radiofrequency ablation (IS-RFA) followed by uncovered SEMS placement for the management of occluded SEMSs.

METHODS

From 2016 to 2020, 48 patients with recurrent biliary obstruction due to tumor ingrowth or overgrowth after SEMS placement for pancreatobiliary cancer in 3 tertiary hospitals were analyzed. For distal MBO, patients in the RFA group were treated with IS-RFA and uncovered SEMS placement, and those in the control group were treated with uncovered SEMS placement alone. Patients in both groups were matched on the basis of propensity scores in a 1:1 ratio.

RESULTS

The median time to recurrent biliary obstruction (TRBO) was 117 days in the RFA group and 82.5 days in the control group (P = .029). No significant differences in median overall survival were detected between the 2 groups (170 days vs 72 days; P = .902). No significant adverse events were reported after the second SEMS placement in either group, but 2 cases of mild cholangitis were reported in the control group. Ablation was interrupted in 5 patients (35.7%) of the RFA group owing to in-stent contact, but sufficient ablative energy was delivered in the majority of the patients (92.9%) after IS-RFA was repeated in the same session.

CONCLUSIONS

IS-RFA followed by an uncovered SEMS is safe and feasible and may improve TRBO as a stent revision for occluded SEMSs in pancreatobiliary cancer.

ACG Clinical Guideline: Diagnosis and Management of Biliary Strictures

A biliary stricture is an abnormal narrowing in the ductal drainage system of the liver that can result in clinically and physiologically relevant obstruction to the flow of bile. The most common and ominous etiology is malignancy, underscoring the importance of a high index of suspicion in the evaluation of this condition. The goals of care in patients with a biliary stricture are confirming or excluding malignancy (diagnosis) and reestablishing flow of bile to the duodenum (drainage); the approach to diagnosis and drainage varies according to anatomic location (extrahepatic vs perihilar). For extrahepatic strictures, endoscopic ultrasound-guided tissue acquisition is highly accurate and has become the diagnostic mainstay. In contrast, the diagnosis of perihilar strictures remains a challenge. Similarly, the drainage of extrahepatic strictures tends to be more straightforward and safer and less controversial than that of perihilar strictures. Recent evidence has provided some clarity in multiple important areas pertaining to biliary strictures, whereas several remaining controversies require additional research. The goal of this guideline is to provide practicing clinicians with the most evidence-based guidance on the approach to patients with extrahepatic and perihilar strictures, focusing on diagnosis and drainage.

Palliative Care in Cholangiocarcinoma

This chapter details all aspects of the general principles of palliative care for advanced stage cholangiocarcinoma patients. These include symptoms management, communication guide, advance care planning, and management for bereavement. Surgical and intervention techniques of palliative biliary drainage are described in detail for patients with obstructive jaundice with advanced stage CCA. Additionally, details are provided regarding the establishment of a multidisciplinary palliative care team which is critical to provide the most appropriate multimodal treatment for good quality of life and survival of patients.

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.

Impact of endobiliary radiofrequency ablation on biliary drainage in patients with malignant biliary strictures treated with uncovered self-expandable metal stents: a randomized controlled multicenter trial

BACKGROUND AND AIMS

Endobiliary radiofrequency ablation (RFA), usually combined with endoscopic stent insertion, is a simple procedure with the potential to improve stent patency and patient survival for malignant biliary obstruction. We conducted this randomized multicenter trial to evaluate the impact of RFA on stent patency.

METHODS

Eighty-six patients with malignant biliary obstruction and nonresectable tumors (pancreatic carcinoma, cholangiocarcinoma, or metastases) were included and randomly assigned to receive a self-expandable metal stent (SEMS) only (n = 44) or RFA followed by SEMS insertion (RFA+SEMS, n = 42). The primary outcome measure was stent patency after 3 and 6 months; secondary outcome measures were patient survival and early adverse events within 30 days.

RESULTS

Technical success rates for RFA and stent insertion were 100% and 98.8%, respectively. Stent patency after 3 and 6 months did not differ significantly between groups (RFA+SEMS group, 73.1% and 33.3%, respectively; SEMS-only group, 81.8% and 52.4%, respectively; P = .6). Similarly, the addition of RFA did not impact overall survival (hazard ratio, .72; P = .389 for RFA+SEMS). The adverse event rate in the RFA+SEMS group was 10.5% compared with 2.3% in the SEMS-only group, without a statistically significant difference (P = .18).

CONCLUSIONS

RFA as an addition to SEMS implantation had no positive impact on patency rate or survival. (Clinical trial registration number: DRKS00018993.).

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.

Endoscopic palliation of malignant biliary obstruction

Malignant biliary obstruction often presents with challenges requiring the endoscopist to assess the location of the lesion, the staging of the disease, the eventual resectability and patient preferences in term of biliary decompression. This review will focus on the different modalities available in order to offer the most appropriate palliation, such as conventional endoscopic retrograde cholangiopancreatography, endoscopic ultrasound guided biliary drainage as well as ablative therapies including photodynamic therapy or radiofrequency ablation.

Efficacy and safety of percutaneous endobilliary radiofrequency ablation with a novel temperature-controlled catheter in malignant biliary strictures

Purpose

The purpose of this study is to evaluate the efficacy and safety of temperature-controlled endobilliary radio-frequency ablation (EB-RFA) followed by metal stent placement for nonresectable malignant biliary strictures.

Material and methods

From May 2017 to March 2021, 18 patients with malignant biliary obstruction who had undergone percutaneous EB-RFA and stent placement (n = 9) or stent placement only (n = 9) were included in this retrospective study. Outcomes were stent patency, technical and clinical success, overall survival, and 30-day complication rate. Kaplan-Meier and Cox regression analyses were performed to examine the relationship of EB-RFA with stent patency and overall survival.

Results

The clinical and technical success rate for each group was 100%. The median stent patency was 128 days (95% CI: 122.2-133.8) in the EB-RFA group and 86 days (95% CI: 1.2-170.7) in the control group. It was significantly longer in the study group (p = 0.012). The mean overall survival was 267.7 ± 68.5 days (95% CI: 133.3-402.2) in the study group and 239.6 ± 33.9 days (95% CI: 173.1-306.2) in the control group. Log-rank test showed there was not a statistically significant difference in overall survival rates (p = 0.302). There were no major complications and no statistically significant difference in cholangitis rates (p = 0.620).

Conclusions

Percutaneous temperature-controlled EB-RFA combined with biliary stent placement for malignant biliary obstruction can be safe and feasible, and effectively increase stent patency.

Impact of Endoluminal Radiofrequency Ablation on Immunity in Pancreatic Cancer and Cholangiocarcinoma

Radiofrequency ablation (RFA) is a mini-invasive loco-regional ablation technique that is increasingly being used as a palliative treatment for pancreatic cancer and cholangiocarcinoma. Ablation-triggered immune system stimulation has been proposed as a mechanism behind the systemic effects of RFA. The aim of our study was to investigate the immune response to endoluminal biliary RFA. Peripheral blood samples were collected from patients with pancreatic cancer and cholangiocarcinoma randomised to receive endoluminal biliary radiofrequency ablation + stent (19 patients) or stent only (21 patients). We observed an early increase in IL-6 levels and a delayed increase in CXCL1, CXCL5, and CXCL11 levels as well as an increase in CD8+ and NK cells. However, these changes were not specific to RFA treatment. Explicitly in response to RFA, we observed a delayed increase in serum CXCL1 levels and an early decrease in the number of anti-inflammatory CD206+ blood monocytes. Our study provides the first evidence of endoluminal biliary RFA-based regulation of the systemic immune response in patients with pancreatic cancer and cholangiocarcinoma. These changes were characterised by a general inflammatory response. RFA-specific activation of the adaptive immune system was not confirmed.

Comparative efficacy and safety of local palliative therapeutics for unresectable malignant biliary obstruction: a Bayesian network meta-analysis

BACKGROUND

Both radiofrequency ablation (RFA), photodynamic therapy (PDT), and biliary stent alone are common local palliative therapies for unresectable malignant biliary obstruction (MBO), but the best modality is uncertain.

RESEARCH DESIGN AND METHODS

Embase, Cochrane Library, PubMed, and Web of Science were systematically searched up to 30 January 2022, for eligible studies that compared either two or all modalities in unresectable MBO.

RESULTS

Thirty-three studies with 2974 patients were included in this study. The PDT+Stent and RFA+Stent groups had better overall survival and longer mean survival time than Stent alone (all P < 0.05). Moreover, patients with RFA+Stent demonstrated better mean duration of stent patency (MD: 2.0, 95%CI,1.1 to 2.8, P < 0.05) than Stent alone. The three modalities had similar postoperative mild bleeding, cholangitis, and pancreatitis (all P ≥ 0.05). According to network ranking, PDT+Stent was most likely to provide better survival, RFA+Stent was most likely to maintain stent patency.

CONCLUSIONS

RFA or PDT plus biliary stent is effective and safe local palliative therapy for unresectable MBO, but the current studies cannot absolutely determine which modality is the best. We should offer patients the most appropriate treatment according to the advantage of each therapy and the patient's performance status.

Local palliative therapies for unresectable malignant biliary obstruction: radiofrequency ablation combined with stent or biliary stent alone? An updated meta-analysis of nineteen trials

BACKGROUND

Recently, there has been a burgeoning interest in radiofrequency ablation combined with stent (RFA + Stent) for unresectable malignant biliary obstruction (MBO). This study aimed to perform a meta-analysis to evaluate the efficacy and safety of RFA + Stent compared with biliary stent alone.

METHODS

We searched PubMed, Cochrane Library, Embase, and Web of Science databases from their inception dates to June 20, 2021, for studies that compared RFA + Stent and stent alone for unresectable MBO. The main outcomes were survival, patency, and adverse effects. All meta-analyses were calculated using the random-effects model.

RESULTS

A total of 19 studies involving 1946 patients were included in this study. Compared with stent alone, RFA + Stent was significantly associated with better overall survival (HR 0.55; 95% CI 0.48, 0.63; P < 0.00001), longer mean survival time (SMD 2.20; 95% CI 1.17, 3.22; P < 0.0001), longer mean stent patency time (SMD 1.37; 95% CI 0.47, 2.26; P = 0.003), higher stent patency at 6 months (OR 2.82; 95% CI 1.54, 5.18; P = 0.0008). The two interventions had similar incidence of postoperative abdominal pain (OR 1.29; 95% CI 0.94, 1.78; P = 0.11), mild bleeding (OR 1.28; 95% CI 0.65, 2.54; P = 0.48), cholangitis (OR 1.09; 95% CI 0.76, 1.55; P = 0.65), pancreatitis (OR 1.39; 95% CI 0.82, 2.38; P = 0.22). Furthermore, the serum bilirubin levels and stricture diameter after operations were significantly alleviated than before operations, but the degree of alleviation between the two groups were not significantly different (all P > 0.05).

CONCLUSION

Although the alleviation of serum bilirubin and stricture diameter did not differ between the two interventions, RFA + Stent can significantly improve the survival and stent patency with comparable procedure-related adverse events than stent alone. Thus, RFA + Stent should be recommended as an attractive alternative to biliary stent alone for patients with unresectable MBO.

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.

Impact of regular additional endobiliary radiofrequency ablation on survival of patients with advanced extrahepatic cholangiocarcinoma under systemic chemotherapy

Prognosis of patients with advanced extrahepatic cholangiocarcinoma (eCCA) is poor. The current standard first-line treatment is systemic chemotherapy (CT) with gemcitabine and a platinum derivate. Additionally, endobiliary radiofrequency ablation (eRFA) can be applied to treat biliary obstructions. This study aimed to evaluate the additional benefit of scheduled regular eRFA in a real-life patient cohort with advanced extrahepatic cholangiocarcinoma under standard systemic CT. All patients with irresectable eCCA treated at University Hospital Bonn between 2010 and 2020 were eligible for inclusion. Patients were stratified according to treatment: standard CT (n = 26) vs. combination of eRFA with standard CT (n = 40). Overall survival (OS), progression free survival (PFS), feasibility and toxicity were retrospectively analyzed using univariate and multivariate approaches. Combined eRFA and CT resulted in significantly longer median OS (17.3 vs. 8.6 months, p = 0.004) and PFS (12.9 vs. 5.7 months, p = 0.045) compared to the CT only group. While groups did not differ regarding age, sex, tumor stage and chemotherapy treatment regimen, mean MELD was even higher (10.1 vs. 6.7, p = 0.015) in the eRFA + CT group. The survival benefit of concomitant eRFA was more evident in the subgroup with locally advanced tumors. Severe hematological toxicities (CTCAE grades 3 – 5) did not differ significantly between the groups. However, therapy-related cholangitis occurred more often in the combined treatment group (p = 0.031). Combination of eRFA and systemic CT was feasible, well-tolerated and could significantly prolong survival compared to standard CT alone. Thus, eRFA should be considered during therapeutic decision making in advanced eCCA.

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.

[Recent Updates on Endoscopic Retrograde Cholangiography-guided Intraductal Radiofrequency Ablation for Malignant Biliary Stricture]

Malignant biliary strictures are caused by pancreatobiliary cancer and other metastatic malignancies. Most of them are unresectable at diagnosis with a dismal prognosis. Various new ablation methods have been introduced. Of them, ERCP-guided intraductal radiofrequency ablation (ID-RFA) appears to be the most promising minimally invasive endoscopic treatment by delivering a high-frequency alternating current to the target tissue, leading to coagulative necrosis. Thus far, many studies have provided evidence that ERCP-guided ID-RFA is a safe, feasible, and effective treatment modality for stent patency and overall survival. Compared to other ablation treatments, ERCP-guided ID-RFA has several advantages, including ease of delivery, controlled application of thermal energy, low cost, and fewer systemic side effects with an acceptable safety profile. Therefore, ERCP-guided ID-RFA can be considered an adjunctive treatment for the palliation of unresectable malignant biliary strictures. On the other hand, the decision of local ablation treatment should be individualized by multidisciplinary team support due to the lack of comparative studies.

Development of Radiofrequency Ablation Generator and Balloon-Based Catheter for Microendoluminal Thin-Layer Ablation Therapy Using the Rat Duodenum as a Model of Low-Impedance Tissue

Radiofrequency ablation (RFA) is a routinely used, safe, and effective method for the tissue destruction. Often, in case of its application in malignant conditions, the extent of tissue destruction is insufficient due to the size of the target lesion, as well as due to the risk of heat-induced damage to the surrounding organs. Nevertheless, there are conditions requiring superficial precise-depth ablation with preservation of deeper layers. These are represented, for example, by mucosal resurfacing in case of Barrett's esophagus or treatment of recurrent mucosal bleeding in case of chronic radiation proctitis. Recently, new indications for intraluminal RFA use emerged, especially in the pancreatobiliary tract. In the case of intraductal use of RFA (e.g., biliary and pancreatic tract), there are currently available rigid and needle tip catheters. An expandable balloon-based RFA catheter suitable for use in such small-diameter tubular organs could be of benefit due to possible increase of contact between the probe and the target tissue; however, to prevent excessive tissue damage, a compatible generator suitable for low-impedance catheter/tissue is essential. This project aimed to develop a radiofrequency ablation generator and bipolar balloon-based catheter optimized for the application in the conditions of low-impedance tissue and (micro)endoluminal environment. Subsequent evaluation of biological effect in vivo was performed using duodenal mucosa in Wistar rat representing conditions of endoluminal radiofrequency ablation of low-impedance tissue. Experiments confirming the safety and feasibility of RFA with our prototype devices were conducted.

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.

Survival Benefit of Intraductal Radiofrequency Ablation for Malignant Biliary Obstruction: A Systematic Review with Meta-Analysis

BACKGROUND/AIMS

Cholangiocarcinoma (CCA) is a rare but aggressive disease with a poor survival. Recent trials have shown improved survival with intraductal radiofrequency ablation (RFA) therapy. We performed a systematic review with meta-analysis to determine the survival benefit of endoscopic RFA for unresectable extrahepatic CCA with malignant biliary obstruction (MBO).

METHODS

A systematic search from 1970 to 2020 was performed in MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials. gov. We selected eligible studies reporting relative risks, hazard ratios (HRs), or odds ratios, adjusted by controlling for confounding factors of survival rate and stent patency duration, among patients with extrahepatic CCA with MBO treated with RFA with stent insertion or stent insertion only.

RESULTS

A total of eight trials (three randomized and five nonrandomized) with a total of 420 patients were included in the metaanalysis. Pooled overall survival analysis favored RFA treatment with stent insertion (HR, 0.47; 95% confidence interval [CI], 0.34- 0.64; I2=47%; p=0.09); however, no significant difference was found in the duration of stent patency between the groups (HR, 0.79; 95% CI, 0.57-1.09; I2=7%; p=0.36).

CONCLUSION

RFA therapy with stent insertion may confer a survival benefit compared with stent insertion only in patients with CCA and MBO.