Peroral Cholangioscopy-Guided Endoluminal Radiofrequency Ablation and Metal Stenting for the Treatment of Unresectable Perihilar Cholangiocarcinoma

Summary

This report demonstrates a stepwise ERCP-based protocol integrating peroral cholangioscopy-guided biliary mapping, targeted tissue sampling, precise endoluminal radiofrequency ablation, and self-expandable metal stent placement for the management of unresectable perihilar cholangiocarcinoma.

Abstract

Perihilar cholangiocarcinoma is frequently diagnosed at an advanced stage and is often unresectable. Malignant biliary obstruction is a major cause of morbidity and commonly requires palliative biliary drainage. Endoscopic retrograde cholangiopancreatography (ERCP) with stent placement is widely used to relieve obstruction; however, tumor ingrowth and overgrowth frequently result in recurrent biliary stenosis and reduced long-term stent patency. Endoluminal radiofrequency ablation (eRFA) has emerged as an adjunctive treatment to improve local tumor control and maintain biliary drainage. Nevertheless, conventional eRFA is generally performed under fluoroscopic guidance alone, which may limit accurate delineation of tumor extent and precise energy delivery. This video article presents a single-case technical demonstration of a stepwise ERCP-based protocol integrating peroral cholangioscopy (POCS)-guided biliary mapping, targeted tissue sampling, precise eRFA, and self-expandable metal stent (SEMS) placement for unresectable perihilar cholangiocarcinoma. Direct visualization with POCS enables assessment of tumor morphology, identification of tumor boundaries, selective cannulation of involved biliary branches, and targeted biopsy acquisition. Information obtained during biliary mapping is subsequently used to define target ablation segments and guide controlled energy delivery. Following eRFA, SEMS are deployed to restore and maintain biliary drainage. This protocol provides a practical framework for visualization-guided endoscopic management of complex hilar biliary strictures and highlights key procedural steps that may improve treatment precision and procedural reproducibility in selected patients with unresectable perihilar cholangiocarcinoma.

Introduction

Cholangiocarcinoma is a highly aggressive malignancy arising from the biliary epithelium and is associated with a poor prognosis worldwide¹. Based on anatomical location, cholangiocarcinoma is classified as intrahepatic, perihilar, or distal, with perihilar cholangiocarcinoma representing the most common subtype and one of the most technically challenging forms to manage². Because most patients present with advanced disease, curative surgical resection is frequently not feasible. Consequently, relief of biliary obstruction remains a primary therapeutic objective.

Obstructive jaundice caused by hilar biliary strictures is a major source of morbidity in advanced cholangiocarcinoma and may result in cholangitis, impaired liver function, and reduced quality of life³. Endoscopic retrograde cholangiopancreatography (ERCP) is the standard minimally invasive approach for biliary decompression and enables internal drainage through plastic or metal stent placement. Compared with plastic stents, self-expandable metal stents provide a larger luminal diameter and longer patency and are therefore preferred for unresectable malignant biliary obstruction^4,5. However, recurrent biliary obstruction caused by tumor ingrowth and overgrowth remains a significant limitation and often necessitates repeat interventions.

To address the limitations of stent-only therapy, endoluminal radiofrequency ablation (eRFA) has emerged as an adjunctive treatment for malignant biliary strictures. Endoluminal radiofrequency ablation delivers thermal energy to intraductal tumor tissue, resulting in coagulative necrosis, reduction of tumor burden, and delayed restenosis, thereby potentially prolonging stent patency^6,7,8. Clinical studies and meta-analyses have demonstrated the technical feasibility and acceptable safety profile of eRFA combined with biliary stenting, with potential benefits in biliary drainage and symptom control⁹. Despite these advantages, eRFA is commonly performed under fluoroscopic guidance alone, relying on indirect imaging to estimate tumor length and treatment extent. This limitation is particularly relevant in perihilar cholangiocarcinoma, where complex biliary anatomy may increase the risk of incomplete treatment or unintended thermal injury to adjacent structures.

Recent advances in peroral cholangioscopy (POCS) have expanded the diagnostic and therapeutic capabilities of ERCP. Direct visualization of the biliary lumen enables detailed assessment of stricture morphology, delineation of tumor boundaries, targeted tissue sampling, and selective access to involved biliary branches. These capabilities may improve diagnostic accuracy and procedural precision during complex biliary interventions^10,11.

The present article describes a stepwise ERCP-based protocol integrating POCS-guided biliary mapping, targeted tissue sampling, precise eRFA, and self-expandable metal stent placement in a representative case of unresectable perihilar cholangiocarcinoma. The protocol emphasizes selective biliary access, visualization-guided treatment planning, and controlled segmental ablation. The objective is to provide a practical procedural framework for the application of this technique in complex hilar biliary strictures.

Case presentation:

An 85-year-old female patient presented with jaundice and abdominal distension for more than 10 days. She initially sought medical attention at a local hospital, where obstructive jaundice was suspected and conservative treatment was administered. However, her symptoms did not improve, and she was subsequently referred to our institution for further evaluation and management.

Laboratory testing on admission revealed markedly elevated serum bilirubin levels. Computed tomography (CT) demonstrated a space-occupying lesion within the bile duct accompanied by intrahepatic bile duct dilatation, raising suspicion for malignant hilar biliary obstruction. Given the patient's advanced age and elevated surgical risk, a comprehensive evaluation was performed to assess suitability for radical surgery. Cardiopulmonary function and overall clinical status were considered during multidisciplinary assessment. In addition, the patient and family expressed reluctance to pursue major curative surgery.

Based on the clinical presentation, imaging findings, and treatment preferences, an endoscopic approach was selected for further diagnosis and management. Written informed consent was obtained before all procedures.

Diagnosis, assessment, and plan:

Following pre-procedural evaluation, a staged ERCP-based strategy was adopted. During the first ERCP session, cholangiography demonstrated a hilar biliary stricture with impaired guidewire advancement. Peroral cholangioscopy (POCS) was subsequently performed, enabling direct visualization of an intraductal tumor characterized by irregular mucosal changes and identifiable proximal and distal margins. Selective access to the involved bile duct branches was achieved under direct visualization, allowing systematic biliary mapping and assessment of tumor extent.

Targeted biopsy specimens were obtained from the lesion under direct POCS guidance without immediate complications. Histopathological examination subsequently confirmed the diagnosis of perihilar cholangiocarcinoma. Therapeutic intervention was deferred pending histopathological confirmation and treatment discussion with the patient and family.

After confirmation of malignancy, the recorded POCS findings, biliary mapping results, and pre-procedural imaging studies were reviewed to assess tumor location, longitudinal extent, and biliary branch involvement. Based on these findings, target ablation segments were identified and a treatment plan was developed consisting of endoluminal radiofrequency ablation (eRFA) followed by self-expandable metal stent (SEMS) placement during a second ERCP session.

Protocol

This study was approved by the Ethics Committee of the Second Affiliated Hospital of Guangzhou Medical University. The research tools used in this protocol are listed in the Table of Materials.

1. Informed consent

1. The patient and family were informed of the planned procedures, expected benefits, potential risks, and available alternatives. Written informed consent was obtained before treatment.

2. Pre-procedural evaluation and preparation

1. Routine laboratory testing, including complete blood count, bilirubin, albumin, and coagulation studies, was performed before treatment.
2. Computed tomography (CT) and magnetic resonance cholangiopancreatography (MRCP) were reviewed to evaluate biliary anatomy, lesion extent, and intrahepatic bile duct involvement.

3. First ERCP: diagnostic evaluation and biliary mapping

1. The patient was placed in the prone position under general anesthesia with endotracheal intubation. A side-viewing duodenoscope was advanced into the second portion of the duodenum, and standard biliary cannulation was achieved under fluoroscopic guidance (Figure 1A).
2. Contrast medium was injected to obtain a cholangiogram and evaluate the location and extent of hilar biliary obstruction. Guidewire advancement toward the proximal bile duct was performed under fluoroscopic guidance (Figure 1B).
3. A peroral cholangioscopy (POCS) system was introduced through the working channel of the duodenoscope and advanced into the bile duct along the guidewire (Figure 1C). Selective cannulation of the involved bile duct branches was performed under direct visualization (Figure 1D).
4. Direct cholangioscopic examination was used to assess tumor morphology, surface characteristics, and tumor margins (Figure 1E). Tumor involvement across biliary branches was documented to generate a biliary map for treatment planning.
5. Targeted biopsy specimens were obtained under direct visual guidance using cholangioscopy-guided biopsy forceps (Figure 1F,G; Figure 2).

Figure 1: First ERCP session: diagnostic evaluation and biliary mapping. (A) Standard biliary cannulation. (B) Fluoroscopic assessment of guidewire looping or resistance caused by the hilar lesion. (C) Advancement of the peroral cholangioscopy (POCS) system under fluoroscopic guidance. (D) Selective cannulation of the involved bile duct branch under direct POCS visualization. (E) Endoscopic visualization of the intraductal tumor. (F) Targeted biopsy of the lesion under direct visual guidance. (G) Representative biopsy specimens were obtained from different regions of the lesion. Please click here to view a larger version of this figure.

Figure 2: Representative biliary mapping findings. Visualization-guided assessment of tumor extent and biliary branch involvement is used for treatment planning. Please click here to view a larger version of this figure.

4. Second ERCP: endoluminal radiofrequency ablation and stent placement

1. Following histopathological confirmation of cholangiocarcinoma, a second ERCP session was performed.
2. The target bile duct branches were re-accessed according to the previously established biliary map. The proximal and distal boundaries of the planned ablation segments were identified (Figure 3A,B).
3. A radiofrequency catheter was positioned under fluoroscopic guidance, and thermal energy was delivered using predefined settings of 10 W for 80 s per treatment cycle¹². Segmental ablation was performed while maintaining stable catheter positioning and avoiding overlap between ablation zones.
4. An uncovered self-expandable metal stent (10 mm × 80 mm) was advanced over the guidewire and deployed across the ablated biliary stricture under fluoroscopic guidance (Figure 3C,D). A nasobiliary drainage catheter was placed when additional drainage was considered necessary (Figure 3E).
5. A final cholangiogram was performed to confirm adequate bile duct patency and satisfactory biliary drainage. All devices were subsequently withdrawn.

Figure 3: Second ERCP session: endoluminal radiofrequency ablation (eRFA) and stent placement. (A) Identification of the proximal tumor boundary in the right hepatic duct (RHD). (B) Identification of the distal tumor boundary in the common hepatic duct (CHD). (C) Placement of an uncovered self-expandable metal stent (SEMS). (D) Fluoroscopic confirmation of stent deployment. (E) Placement of a nasobiliary drainage catheter. Please click here to view a larger version of this figure.

5. Post-procedural management

1. The patient was monitored for procedure-related complications, including abdominal pain, fever, pancreatitis, bleeding, and cholangitis.
2. Liver function tests and serum bilirubin levels were assessed after the procedure to evaluate biliary drainage.
3. Clinical follow-up was performed to assess symptom improvement, stent patency, and overall clinical status.

Results

The first ERCP session was completed successfully. Cholangiography demonstrated a hilar biliary stricture with impaired guidewire advancement. Peroral cholangioscopy (POCS) enabled direct visualization of an intraductal tumor with an irregular mucosal surface and identifiable proximal and distal margins. Selective access to the involved bile duct branches was achieved under direct visualization, allowing systematic biliary mapping. Targeted biopsy specimens were obtained without immediate complications, and histopathological examination confirmed perihilar cholangiocarcinoma.

Following histopathological confirmation, a second ERCP session was performed. The target bile duct branches were re-accessed according to the previously established biliary map. Segmental endoluminal radiofrequency ablation (eRFA) was completed successfully with stable catheter positioning and clear fluoroscopic landmarks. No procedure-related perforation, bleeding, or bile duct injury was observed during the procedure. An uncovered self-expandable metal stent was subsequently deployed across the treated biliary stricture, resulting in immediate restoration of biliary flow.

Post-procedural laboratory evaluation demonstrated a marked reduction in serum bilirubin levels, with total bilirubin decreasing from 213.8 µmol/L before treatment to 67.6 µmol/L after treatment (Table 1). During follow-up, the stent remained patent without documented occlusion, and no major procedure-related adverse events were observed. The patient ultimately died of cardiopathy 2 years after the procedure.

	The first ERCP	The second ERCP
Operative time	42	55
( min )
Preoperative TB	213.8	187
(μmol/L)
Preoperative DB	189.4	171
(μmol/L)
Postoperative day1 TB	190.8	164.1
(μmol/L)
Postoperative day1 DB	162.3	132.9
(μmol/L)
Postoperative day3 TB	209.6	82.7
(μmol/L)
Postoperative day3 DB	181.2	67.6
(μmol/L)

This case demonstrates the successful application of POCS-guided biliary mapping, targeted tissue sampling, endoluminal radiofrequency ablation, and metal stent placement in a patient with unresectable perihilar cholangiocarcinoma.
Table 1: Procedural and laboratory findings during the two ERCP sessions. Operative duration and peri-procedural bilirubin measurements were obtained before and after each procedure.

Discussion

Perihilar cholangiocarcinoma is an aggressive malignancy originating from the biliary epithelium and is frequently diagnosed at an advanced stage because of its insidious onset and lack of specific early symptoms. Most patients are not candidates for curative surgical resection because of advanced local extension, vascular involvement, or poor functional reserve. Consequently, endoscopic palliation using ERCP-guided biliary drainage plays a central role in symptom control and supportive care. However, effective management of hilar biliary obstruction remains challenging because of the complex biliary anatomy, multifocal tumor spread, and risk of incomplete drainage.

Peroral cholangioscopy (POCS) has significantly expanded the diagnostic and therapeutic capabilities of ERCP by enabling direct visualization of the bile duct lumen¹³. Compared with fluoroscopy-guided techniques alone, POCS improves the assessment of indeterminate biliary strictures by allowing direct evaluation of mucosal patterns, tumor morphology, and longitudinal tumor extension¹⁴. Meta-analyses have demonstrated that POCS-guided visual assessment combined with biopsy provides substantially higher diagnostic accuracy for malignant biliary strictures than conventional ERCP-based sampling methods¹⁵. In addition, POCS has been shown to be particularly useful for mapping the superficial extension of cholangiocarcinoma^16,17,18. Despite these advantages, POCS-assisted procedures require dedicated equipment and advanced endoscopic expertise, and their use may be limited by cost, availability, and procedural complexity¹¹. Furthermore, reported adverse events associated with POCS, including cholangitis and pancreatitis, underscore the importance of appropriate patient selection and procedural standardization¹⁹.

Endoluminal radiofrequency ablation (eRFA) has emerged as an adjunctive endoscopic therapy for malignant biliary strictures. By inducing controlled coagulative necrosis within the bile duct, eRFA aims to reduce local tumor burden and delay restenosis following stent placement^4,5,6,7. Clinical studies and meta-analyses have demonstrated the technical feasibility and acceptable safety profile of eRFA combined with biliary stenting^12,14,20. In particular, a recent systematic review and meta-analysis reported that intraductal radiofrequency ablation combined with biliary stenting may improve stent patency and clinical outcomes in patients with unresectable perihilar cholangiocarcinoma¹³. Nevertheless, most reported eRFA procedures have been performed under fluoroscopic guidance without direct visualization, which may limit accurate delineation of tumor extent and precise energy delivery, particularly in anatomically complex hilar strictures.

The present case highlights several potential advantages of combining POCS with eRFA in the management of unresectable perihilar cholangiocarcinoma²¹. Direct visualization enabled selective access to involved bile duct branches, systematic biliary mapping, and accurate delineation of tumor margins before energy delivery. These capabilities were particularly valuable in this patient because of the complex hilar anatomy and the need for precise treatment planning. In addition, cholangioscopy-guided biopsy provided histopathological confirmation of malignancy and facilitated subsequent treatment planning. Recent advances in POCS technology, including improved image quality, dedicated irrigation systems, and single-operator platforms, have enhanced the feasibility of cholangioscopy-assisted interventions in complex biliary disease^22,23.

Several limitations should be acknowledged. First, this report describes a single patient and therefore does not permit conclusions regarding comparative efficacy, long-term outcomes, or generalizability. Second, the favorable clinical course observed in this case may not be representative of all patients with unresectable perihilar cholangiocarcinoma. Third, POCS-assisted procedures require specialized equipment and experienced endoscopists, which may limit broader implementation¹¹. Finally, larger prospective studies are needed to clarify optimal patient selection criteria, determine ideal ablation parameters, and evaluate the long-term clinical impact of POCS-guided eRFA.

Despite these limitations, this case illustrates the feasibility of integrating POCS-guided biliary mapping, targeted tissue sampling, eRFA, and metal stent placement into a single treatment strategy for complex hilar biliary obstruction. The successful technical outcome, effective biliary drainage, and absence of major procedure-related adverse events observed in this patient support further investigation of this visualization-guided approach in selected patients with unresectable perihilar cholangiocarcinoma.

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Name of Material/ Equipment	Company	Catalog Number	Comments/Description
Bile duct self-expandable metal stent	Boston Scientific Corp.	RX4966	Biliary drainage
Biopsy forceps	Micro-Tech Corp.	BF10006	obtain targeted tissue samples
Catheter and guidewire	Boston Scientific Corp.	M00583100	Used for cannulation of bile duct
Duodenoscope	Olympus Corp.	TJF-260V	Used for ERCP
eRFA catheter	Boston Scientific Corp.	M00500070	Perform radiofrequency ablation on the diseased tissue
Nasobiliary duct	LeoMed Corp.	L14725D	Biliary drainage
Peroralcholangioscopy	Micro-Tech Corp.	CDS22001	Inspect the bile duct