Role of photodynamic therapy and intraductal radiofrequency ablation in cholangiocarcinoma

Novel self-expandable stent-based endobiliary radiofrequency ablation for unresectable malignant biliary obstruction

BACKGROUND AND AIMS

Endobiliary radiofrequency ablation (RFA) is an emerging endoscopic palliative adjunctive therapy used for the local treatment of unresectable malignant biliary obstruction (MBO). However, irregular ablation ranges caused by insufficient electrode-to-bile duct contact pose a significant obstacle. We investigated the feasibility of a self-expandable stent (SES)-based electrode with a customized RFA generator in the porcine liver and common bile duct (CBD).

METHODS

An SES-RFA system with polarity switching was developed to perform endobiliary RFA. The ablation ranges of 20 ablation protocols were evaluated to validate the feasibility of the newly developed RFA system in the porcine liver. Nine of 20 ablation protocols were selected for evaluation in the porcine CBD with cholangiography, endoscopy, and histologic and immunohistochemical analysis.

RESULTS

The SES-RFA system with polarity switching was successfully constructed and demonstrated high accuracy and reproducibility. The ablation area was clearly identified between the 2 SESs. The ablation ranges and degree of mucosal damage, including terminal deoxynucleotidyl transferase-mediated dUTP nick and labeling-positive and heat shock protein 70-positive depositions, increased proportionally with ablation protocols in the porcine liver and CBD (all P < .05). Ablation length and depth linearly increased with ablation protocols from 8.74 ± .25 to 31.25 ± .67 mm and 1.61 ± .09 to 11.94 ± .44 mm, respectively.

CONCLUSIONS

The SES-RFA system with polarity switching between electrodes provided an even circumferential area of ablation and enhanced ablation depth between the electrodes. This novel endobiliary RFA system is a promising modality for local ablation in patients with unresectable MBO.

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.

Radiofrequency ablation in the management of primary hepatic and biliary tumors

In the United States, 80%-90% of primary hepatic tumors are hepatocellular carcinomas and 10%-15% are cholangiocarcinomas (CCA), both with high mortality rate, particularly CCA, which portends a worse prognosis. Traditional management with surgery has good outcomes in appropriately selected patients; however, novel ablative treatment options have emerged, such as radiofrequency ablation (RFA), which can improve the prognosis of both hepatic and biliary tumors. RFA is aimed to generate an area of necrosis within the targeted tissue by applying thermal therapy via an electrode, with a goal to completely eradicate the tumor while preserving surrounding healthy tissue. Role of RFA in management of hepatic and biliary tumors forms the focus of our current mini-review article.

Ablative therapies of the biliary tree

Cholangiocarcinoma, a malignancy of the epithelial cells in the intrahepatic or extrahepatic biliary tree, is often diagnosed at later stages. Median survival duration ranges from 3 to 9 months with a less than ten percent 5-year survival rate. Thus, often treatment strategies are aimed more towards palliation instead of cure. With the majority of patients presenting with unresectable disease at the time of diagnosis, surgical intervention is not feasible, making less invasive endoscopic therapies more suitable. Initially, biliary stents were utilized for biliary decompression to mitigate cholestatic symptoms and prevent cholangitis; however, this strategy did not prove to provide significant survival benefit. Therefore, efforts to treat the tumor burden itself in addition to maintaining biliary patency became a focus of innovation and research in the endoscopic field. This study has led to the advent of therapies such as photodynamic therapy, radiofrequency ablation, and intraluminal brachytherapy. These options combined with biliary stenting have shown to not only offer the benefit of biliary decompression, but also to potentially improve stent patency and survival. Further, there is an anti-tumor effect of each of these modalities, portending an additional benefit in this subset of patients. Despite numerous retrospective and prospective studies assessing these ablative therapies, there is still a paucity of appropriately powered randomized controlled trials, and further research has yet to be done in the field. This review details the current literature entailing endobiliary ablative strategies.

Photodynamic Therapy: A Compendium of Latest Reviews

Photodynamic therapy (PDT) is a promising therapy against cancer. Even though it has been investigated for more than 100 years, scientific publications have grown exponentially in the last two decades. For this reason, we present a brief compendium of reviews of the last two decades classified under different topics, namely, overviews, reviews about specific cancers, and meta-analyses of photosensitisers, PDT mechanisms, dosimetry, and light sources. The key issues and main conclusions are summarized, including ways and means to improve therapy and outcomes. Due to the broad scope of this work and it being the first time that a compendium of the latest reviews has been performed for PDT, it may be of interest to a wide audience.

Advancements in Endoscopic Biliary Interventions by Gastroenterology

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

Design and Characterization of a Minimally Invasive Bipolar Electrode for Electroporation

OBJECTIVE

To test a new bipolar electrode for electroporation consisting of a single minimally invasive needle.

METHODS

A theoretical study was performed by using Comsol Multiphysics^® software. The prototypes of electrode have been tested on potatoes and pigs, adopting an irreversible electroporation protocol. Different applied voltages and different geometries of bipolar electrode prototype have been evaluated.

RESULTS

Simulations and pre-clinical tests have shown that the volume of ablated area is mainly influenced by applied voltage, while the diameter of the electrode had a lesser impact, making the goal of minimal-invasiveness possible. The conductive pole's length determined an increase of electroporated volume, while the insulated pole length inversely affects the electroporated volume size and shape; when the insulated pole length decreases, a more regular shape of the electric field is obtained. Moreover, the geometry of the electrode determined a different shape of the electroporated volume. A parenchymal damage in the liver of pigs due to irreversible electroporation protocol was observed.

CONCLUSION

The minimally invasive bipolar electrode is able to treat an electroporated volume of about 10 mm in diameter by using a single-needle electrode. Moreover, the geometry and the electric characteristics can be selected to produce ellipsoidal ablation volumes.

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

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

Inoperable Biliary Tract and Primary Liver Tumors: Palliative Treatment Options

Primary liver tumors are most commonly hepatocellular carcinoma and intrahepatic cholangiocarcinoma. Although surgical resection offers a chance for cure, these tumors generally present at a late, inoperable stage, necessitating an understanding of noncurative and palliative treatment options. These options include ablative therapies, including radiofrequency ablation; intra-arterial therapies, including transcatheter chemoembolization; biliary decompression; radiotherapy; systemic therapies, including traditional chemotherapeutic agents; and molecular therapies, such as sorafenib. Selection of nonoperative treatment depends on patient and tumor factors as well as institutional resources and expertise.

Hepatopulmonary syndrome after radiofrequency ablation of recurrent intrahepatic cholangiocarcinoma: a case report

Background

Radiofrequency ablation (RFA) is one of the definitive treatment modalities for liver cancer and has been increasingly used in the scenario of small-sized liver cancer. It is generally believed that RFA is minimally invasive and associated with a favorable safety profile in liver cancer patients. However, this interventional technique is subject to some morbidity in high-risk patients, such as those with complicating cirrhosis or a liver cancer located at a refractory segment.

Methods

Herein, we report the case of a middle-aged woman who developed acute liver failure with a complicating respiratory failure after RFA of recurrent intrahepatic cholangiocarcinoma.

Results

A diagnosis of hepatopulmonary syndrome was established. The patient was hospitalized in the intensive care unit for mechanical ventilation. Finally, the patient recovered from an eventful clinical course and survived free of recurrence until the last follow-up visit at 1 year after the discharge.

Conclusion

Our case report warns that hepatopulmonary syndrome, a less common morbidity secondary to liver cancer RFA, should require timely identification and appropriate management due to its life-threatening outcome.

Endoscopic Retrograde Cholangiopancreatography-Guided Ablation for Cholangiocarcinoma

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

Validation of the Mayo Clinic Staging System in Determining Prognoses of Patients With Perihilar Cholangiocarcinoma

BACKGROUND & AIMS

Most systems for staging perihilar cholangiocarcinoma (PHC) have been developed for the minority of patients with resectable disease. The recently developed Mayo Clinic system for staging PHC requires only clinical and radiologic variables, but has not yet been validated. We performed a retrospective study to validate the Mayo Clinic staging system.

METHODS

We identified consecutive patients with suspected PHC who were evaluated and treated at 2 tertiary centers in The Netherlands, from January 2002 through December 2014. Baseline characteristics (performance status, carbohydrate antigen 19-9 level) used in the staging system were collected from medical records and imaging parameters (tumor size, suspected vascular involvement, and metastatic disease) were reassessed by 2 experienced abdominal radiologists. Overall survival was analyzed using the Kaplan-Meier method and comparison of staging groups was performed using the log-rank test and Cox proportional hazard regression analysis. Discriminative performance was quantified by the concordance index and compared with the radiologic TNM staging of the American Joint Committee on Cancer (7th ed).

RESULTS

PHCs from 600 patients were staged according to the Mayo Clinic model (23 stage I, 80 stage II, 357 stage III, and 140 stage IV). The median overall survival time was 11.6 months. The median overall survival times for patients with stages I, II, III, and IV were 33.2 months, 19.7 months, 12.1 months, and 6.0 months, respectively; with hazard ratios of 1.0 (reference), 2.02 (95% confidence interval [CI], 1.14-3.58), 2.71 (95% CI, 1.59-4.64), and 4.00 (95% CI, 2.30-6.95), respectively (P < .001). The concordance index score was 0.59 for the entire cohort (95% CI, 0.56-0.61). The Mayo Clinic model performed slightly better than the radiologic American Joint Committee on Cancer TNM system.

CONCLUSIONS

In a retrospective study of 600 patients with PHC, we validated the Mayo Clinic system for staging PHC. This 4-tier staging system may aid clinicians in making treatment decisions, such as referral for surgery, and predicting survival times.

Locoregional therapies in cholangiocarcinoma

Cholangiocarcinoma is a rare and aggressive malignancy of the biliary tract. Complete surgical resection can be curative, but the majority of patients are diagnosed with advanced disease and usually die within a year of diagnosis. Most deaths are attributable to local disease progression rather than distant metastases, supporting the use of locoregional therapies. There is evidence that locoregional therapies can provide local tumor control resulting in increased survival while avoiding some of the side effects of systemic treatments, increasing potential treatment options for patients who may be unsuitable for systemic palliative treatments. This review considers the evidence for locoregional therapies in cholangiocarcinoma, which can be classified into endoscopic, vascular, percutaneous and radiation oncological therapies. Current guidelines do not recommend the routine use of locoregional therapies due to a lack of prospective data, but the results of ongoing trials are likely to increase the evidence base and impact on clinical practice.

Palliative treatment with radiation-emitting metallic stents in unresectable Bismuth type III or IV hilar cholangiocarcinoma

Background

The emerging data for stenting in combination with brachytherapy in unresectable hilar cholangiocarcinoma are encouraging. The aim of this study was to evaluate the efficacy and safety of radiation-emitting metallic stents (REMS) for unresectable Bismuth type III or IV hilar cholangiocarcinoma.

Patients and methods

Consecutive patients who underwent percutaneous placement with REMS or uncovered self-expandable metallic stent (SEMS) for unresectable Bismuth type III or IV hilar cholangiocarcinoma between September 2011 and April 2016 were identified into this retrospective study. Data on patient demographics and overall survival, functional success, stent patency and complications were collected at the authors’ hospital.

Results

A total of 59 patients were included: 33 (55.9%) in the REMS group and 26 (44.1%) in the SEMS group. The median overall survival was 338 days in the REMS group and 141 days in the SEMS group (p<0.001). The median stent patency time was 385 days for REMS and 142 days for SEMS (p<0.001). The functional success rate (87.9% vs 84.6%, p=0.722) and incidence of overall complications (27.3% vs 26.9%, p=0.999) did not differ in the two groups.

Conclusions

Placement with REMS is safe and effective in palliation for unresectable Bismuth type III or IV hilar cholangiocarcinoma, and seems to prolong survival as well as patency of stent in these patients.

Malignant biliary obstruction: From palliation to treatment

Malignant obstruction of the bile duct from cholangiocarcinoma, pancreatic adenocarcinoma, or other tumors is a common problem which may cause debilitating symptoms and increase the risk of subsequent surgery. The optimal treatment - including the decision whether to treat prior to resection - depends on the type of malignancy, as well as the stage of disease. Preoperative biliary drainage is generally discouraged due to the risk of infectious complications, though some situations may benefit. Patients who require neoadjuvant therapy will require decompression for the prolonged period until attempted surgical cure. For pancreatic cancer patients, self-expanding metallic stents are superior to plastic stents for achieving lasting decompression without stent occlusion. For cholangiocarcinoma patients, treatment with percutaneous methods or nasobiliary drainage may be superior to endoscopic stent placement, with less risk of infectious complications or failure. For patients of either malignancy who have advanced disease with palliative goals only, the choice of stent for endoscopic decompression depends on estimated survival, with plastic stents favored for survival of < 4 mo. New endoscopic techniques may actually extend stent patency and patient survival for these patients by achieving local control of the obstructing tumor. Both photodynamic therapy and radiofrequency ablation may play a role in extending survival of patients with malignant biliary obstruction.