Endoscopic ultrasound-guided application of a new internally gas-cooled radiofrequency ablation probe in the liver and spleen of an animal model: a preliminary study

Endoscopic ultrasound for the diagnosis and treatment of primary hepatocellular carcinoma

Chronic liver disease has emerged as a significant global concern, with primary hepatocellular carcinoma (HCC) representing a critical consequence of this disease. However, early detection of HCC remains challenging in clinical practice. Recently, there has been a growing interest in applying endoscopic ultrasound (EUS) as a diagnostic tool for gastrointestinal diseases. Nevertheless, using EUS to diagnose and treat HCC is uncommon. In this review we described the diagnostic and therapeutic applications of EUS in primary HCC and evaluated its clinical significance. The diagnostic procedures primarily involve EUS-guided fine-needle biopsy or aspiration, assessment of metastatic lymph nodes and portal vein thrombosis, portal pressure monitoring, and portal vein blood collection. Treatment mainly includes EUS-guided tumor ablation, brachytherapy, injectable chemotherapy, and managing variceal hemorrhage related to portal hypertension.

Endohepatology: The endoscopic armamentarium in the hand of the hepatologist

ABSTRACT

Recent advances in the field of hepatology include new and effective treatments for viral hepatitis. Further effort is now being directed to other disease entities, such as non-alcoholic fatty liver disease, with an increased need for assessment of liver function and histology. In fact, with the evolving nomenclature of fat-associated liver disease and the emergence of the term "metabolic-associated fatty liver disease" (MAFLD), new diagnostic challenges have emerged as patients with histologic absence of steatosis can still be classified under the umbrella of MAFLD. Currently, there is a growing number of endoscopic procedures that are pertinent to patients with liver disease. Indeed, interventional radiologists mostly perform interventional procedures such as percutaneous and intravascular procedures, whereas endoscopists focus on screening for and treatment of esophageal and gastric varices. EUS has proven to be of value in many areas within the realm of hepatology, including liver biopsy, assessment of liver fibrosis, measurement of portal pressure, managing variceal bleeding, and EUS-guided paracentesis. In this review article, we will address the endoscopic applications that are used to manage patients with chronic liver disease.

Endoscopic procedures in hepatology: Current trends and new developments

Gastrointestinal endoscopy has long been a reliable backbone in the diagnosis and management of hepatobilary disorders and their complications. However, with evolving non-invasive testing, personalised medicine has reframed the utility and necessity of endoscopic screening. Conversely, the growing interest and use of endoscopic ultrasound (EUS) and advanced endoscopy within gastrointestinal units has also opened novel diagnostic and therapeutic avenues for patients with various hepatobiliary diseases. The integration of "advanced endoscopy" within the practice of hepatology is nowadays referred to as "endo-hepatology". In essence, endo-hepatology consists of two pillars: one focusing primarily on disorders of the liver parenchyma, vascular disorders, and portal hypertension, which is mainly captured via EUS, while the other targets the hepatobiliary tract via endoscopic retrograde cholangiopancreatography and advanced imaging. Applications under the umbrella of endo-hepatology include, amongst others, EUS-guided liver biopsy, EUS-guided portal pressure gradient measurement, coil and glue embolisation of gastric varices as well as cholangioscopy. As such endo-hepatology could become an attractive concept wherein advanced endoscopy might reinforce the medical management of patients with hepatobiliary disorders and their complications after initial basic work-up. In this review, we discuss current trends and future developments within endo-hepatology and the remaining hurdles to overcome.

Efficacy and Safety of Endoscopic Ultrasound-Guided Radiofrequency Ablation for Pancreatic Neuroendocrine Tumors: A Systematic Review and Metanalysis

Introduction: The development of dedicated endoscopes and the technical evolution of endoscopic ultrasound (EUS) have allowed a direct approach to pancreatic neoplastic lesions both for diagnosis and treatment. Among the more promising targets are pancreatic neuroendocrine tumors (Pan-NETs). Aim: to describe the evolution of endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) with particular attention to the treatment of PanNETs, focusing on safety and clinical efficacy of the technique. Methods: MEDLINE, Scopus, and Cochrane Library databases were searched for studies reporting about EUS-RFA for the treatment of PanNETs. Studies with outcomes of interest were selected and results were reported to describe clinical success, complications, fol-low-ups, and electrodes used. Clinical success was defined as the disappearance of clinical symp-toms for functional (F-) PanNETs and as complete ablation per nonfunctional (NF)-PanNETs. The pooled data were analyzed by a random-effects model. Results: Nineteen studies were selected, including 183 patients (82 males, 44.8%) with 196 lesions (101 F-PanNETs and 95 NF-PanNETs). Pooled estimates for the overall AE rates for the clinical efficacy were 17.8% (95% CI 9.1-26.4%) and 95.1% (95% CI 91.2-98.9%) for F-PanNETs and 24.6% (95% CI 7.4-41.8%) and 93.4% (95% CI 88.4-98.4%) for NF-PanNETs. Conclusions: EUS-RFA appears to be a mini-invasive technique with a good safety and efficacy profile for the treatment of F- and NF-PanNETs. EUS-RFA could be of-fered as possible alternative to surgery for the treatment of low-grade NF- or F-PanNETs, especially for those patients that are not eligible or are at high-risk for surgery.

EUS-guided intra-tumoral therapies

EUS-guided treatments for focal tumor lesions has been developed since 20 years using at onset of the technique mainly local and guided alcohol injection [1-4]. Pancreatic tumors are the most assessed targeted lesions for EUS treatment because of their accessibility and because EUS management could be a safe alternative to surgery. More and more pancreatic tumors are discovered mainly fortuitously due to the advances in conventional imaging (abdominal ultrasound, CT, MRI) resulting in the question of surgical management of an asymptomatic pancreatic lesion ("incidentaloma") [5-8]. The lesions detected include mostly pancreatic cystic neoplasms (PCN) and neuroendocrine tumors (NET) mainly well differentiated. Clinically, NET are mostly non-functional and do not induce secretory disorders [5-8]. Once their nature is yielded by diagnostic tests like EUS-FNA, incidental nonfunctional NET currently lead to difficult management when their largest diameter is less than 2 cm [2,4,9,10]. EUS-guided treatment for pancreatic adenocarcinoma have also been developed with recent prospective observational study and randomized control study [11,12]. Thus, therapeutic surgical choices could be challenged by EUS- guided treatment [2,4,9].

Long-term outcomes of endoscopic ultrasound-guided laser ablation for liver tumors in the caudate lobe: 5 years of experience

OBJECTIVES

Liver tumor in the caudate lobe is challenging to treat, partly due to its deep location. Endoscopic ultrasound-guided laser ablation (EUS-LA) is a new attractive option for tumors in high-risk or difficult-to-reach locations. This prospective study investigated the long-term efficacy of EUS-LA for tumors in the caudate lobe, and factors that predict outcomes.

METHODS

From June 2016 to July 2021, twenty consecutive patients (aged 56.95 ± 10.06 years) with 25 caudate lobe tumors (15.64 ± 6.37 mm) underwent EUS-LA. Treatment outcomes were assessed and predictive factors were calculated via univariate and multivariate analyses.

RESULTS

Twenty-five tumors achieved complete ablation after the first or second session of EUS-LA. The treatment effectiveness was 100%. During a median follow up of 27 months (3-60), four tumors (16%) developed local tumor progression and 15 patients (75%) experienced intrahepatic distant recurrence. According to univariate and multivariate analyses, the significant prognostic factor of local tumor progression was tumor size >2 cm (p = 0.047). Significant prognostic factors of intrahepatic distant recurrence were: tumor number, alpha-fetoprotein level, and total bilirubin level (p = 0.020, 0.019, 0.010, respectively). No adverse events related to EUS-LA were observed.

CONCLUSION

EUS-LA is a viable, safe, and effective treatment option for patients with liver tumor in the caudate lobe. Tumor size >2 cm increases the risk of post-procedural local tumor progression. Intrahepatic tumor number, and pretreatment alpha-fetoprotein level and total bilirubin level are associated with intrahepatic distant recurrence.

REGISTRATION

Clinicaltrials.gov, ID: NCT02816944(June 29, 2016).

EUS-guided ablation with the HybridTherm Probe as second-line treatment in patients with locally advanced pancreatic ductal adenocarcinoma: A case-control study

Background and Objectives

Data on the clinical efficacy of EUS-guided ablation using the HybridTherm-Probe (EUS-HTP) in locally advanced pancreatic ductal adenocarcinoma (LA-PDAC) are lacking. The aim of the study was to assess the impact of EUS-HTP added to chemotherapy (CT) on overall survival (OS) and progression-free survival (PFS) of LA-PDAC patients with local disease progression (DP) after first-line therapy, compared to CT alone in controls.

Methods

LA-PDAC cases, prospectively treated by EUS-HTP, were retrospectively compared to matched controls (1:2) receiving standard treatment. Study endpoints were the OS and PFS from local DP after first-line therapy, compared through log-rank test calculating hazard ratios and differences in restricted mean OS/PFS time (RMOST/RMPFST) within prespecified time points (4, 6, and 12 months).

Results

Thirteen cases and 26 controls were included. Clinical, tumor, and therapy features before and after first-line therapy were case-control balanced. The median OS and PFS were not significantly improved in cases over controls (months: 7 vs. 5 and 5 vs. 3, respectively). At 4 and 6 months, the RMPFST difference was in favor of cases (P = 0.0001 and P = 0.003, respectively). In cases and controls not candidate to further CT (N = 5 and N = 9), the median OS and PFS were not significantly improved in cases over controls (months: 6 vs. 3 and 4 vs. 2, respectively), but the RMPFST difference was in favor of cases at 4 months (P = 0.002).

Conclusions

In locally progressive PDAC patients experiencing failure of first-line therapy, EUS-HTP achieves a significantly better RMPFST up to 6 months compared to standard treatment, although without a significant impact on OS.

Role of endoscopic ultrasound in anticancer therapy: Current evidence and future perspectives

The digestive system is one of the most common sites of malignancies in humans. Since gastrointestinal tumors represent a massive global health burden both in terms of morbidity and health care expenditures, scientists continuously develop novel diagnostic and therapeutic methods to ameliorate the detrimental effects of this group of diseases. Apart from the well-established role of the endoscopic ultrasound (EUS) in the diagnostic course of gastrointestinal and hepatobiliary malignancies, we have recently become acquainted with a vast array of its therapeutic possibilities. A multitude of previously established, evidence-based methods that might now be guided by the EUS emerged: Radiofrequency ablation, brachytherapy, fine needle injection, celiac plexus neurolysis, and endoscopic submucosal dissection. In this review we endeavored to provide a comprehensive overview of the role of these methods in different malignancies of the digestive system, primarily in the treatment and symptom control in pancreatic cancer, and additionally in the management of hepatic, gastrointestinal tumors, and pancreatic cysts.

A state-of-the-art comprehensive review summarizing the emerging data on endoscopic ultrasound-guided liver diseases management

Liver diseases are among the most common diseases worldwide accounting for substantial morbidity and mortality. Most liver diseases necessitate radiological evaluation or accurate diagnosis and recently for management as well. In the last decade, the application of therapeutic endoscopic ultrasound (EUS) procedure has been increasingly utilized for the management of various liver diseases. In this comprehensive narrative review article, we provide systematic overview on EUS-guided therapeutic interventions in various liver diseases summarizing most updated data regarding technical success, outcomes and safety profiles. Overall, 35 articles have reported on the use of EUS in the treatment of liver diseases with excellent technical success, favorable radiological response and high safety profiles for EUS-guided treatment of solid and cystic liver lesion and for EUS-guided angiotherapy for gastric varices, except for EUS-guided cyanoacrylate glue injection which was associated with life-threatening fatal systemic embolization adverse events. This suggests that EUS-guided intervention is a new promising therapeutic intervention for the treatment of various liver diseases with durable effect and a limited potential for adverse events.

Role of endoscopic ultrasound in the field of hepatology: Recent advances and future trends

The role of endoscopic ultrasound (EUS) as a diagnostic and therapeutic modality for the management of various gastrointestinal diseases has been expanding. The imaging or intervention for various liver diseases has primarily been the domain of radiologists. With the advances in EUS, the domain of endosonologists is rapidly expanding in the field of hepatology. The ability to combine endoscopy and sonography in one hybrid device is a unique property of EUS, together with the ability to bring its probe/transducer near the liver, the area of interest. Its excellent spatial resolution and ability to provide real-time images coupled with several enhancement techniques, such as contrast-enhanced (CE) EUS, have facilitated the growth of EUS. The concept of “Endo-hepatology” encompasses the wide range of diagnostic and therapeutic procedures that are now gradually becoming feasible for managing various liver diseases. Diagnostic advancements can enable a wide array of techniques from elastography and liver biopsy for liver parenchymal diseases, to CE-EUS for focal liver lesions to portal pressure measurements for managing various liver conditions. Similarly, therapeutic advancements range from EUS-guided eradication of varices, drainage of bilomas and abscesses to various EUS-guided modalities of liver tumor management. We provide a comprehensive review of all the different diagnostic and therapeutic EUS modalities available for the management of various liver diseases. A synopsis of all the technical details involving each procedure and the available data has been tabulated, and the future trends in this area have been highlighted.

Endoscopic ultrasound guided hepatic interventions

Intervention for liver disease has predominantly been performed through the percutaneous approach. However, as endoscopic ultrasound (EUS) applications have expanded, there have emerged various EUS-guided interventions for liver disease, a space we call "Endo-Hepatology". EUS-guided liver biopsy can be considered the "forerunner" of Endo-Hepatology and has become a clinical option for patients requiring histologic diagnosis and staging of their liver disease. EUS also enables direct access to the portal vein. Subsequently, many procedures are being explored, such as angiography, measurement of the portosystemic pressure gradient, portal vein sampling to detect cancer cell or DNA, and EUS-guided transhepatic intrahepatic portosystemic shunt creation. Since the transducer is close to the liver, especially the left and caudate lobes, EUS can be used as a rescue when the percutaneous approach is not favorable and EUS-guided treatments of liver tumor, cyst and abscess have been reported. This review summarizes the available studies of EUS-guided intervention in the liver.

Necrosis volume and Choi criteria predict the response to endoscopic ultrasonography-guided HybridTherm ablation of locally advanced pancreatic cancer

Background and study aims  Endoscopic ultrasound (EUS)-guided ablation of pancreatic ductal adenocarcinoma (PDAC) with HybridTherm-Probe (EUS-HTP) is feasible and safe, but the radiological response and ideal tool to measure it have not been investigated yet. The aims of this study were to: 1) assess the radiological response to EUS-HTP evaluating the vital tumor volume reduction rate, Response Evaluation Criteria in Solid Tumors (RECIST1.1) and Choi criteria; 2) determine the prognostic predictive yield of these criteria. Patients and methods  A retrospective analysis was performed of patients with locally advanced PDAC after primary treatment or unfit for chemotherapy prospectively treated by EUS-HTP. Computed tomography scan was performed 1 month after EUS-HTP to evaluate: 1) vital tumor volume reduction rate (VTVRR) by measuring necrosis and tumor volumes through a computer-aided detection system; and 2) RECIST1.1 and Choi criteria. Results  EUS-HTP was feasible in 22 of 31 patients (71 %), with no severe adverse events. Median post-HTP survival was 7 months (1 - 35). Compared to pre-HTP tumor volume, a significant 1-month VTVRR (mean 21.4 %) was observed after EUS-HTP ( P  = 0.005). We identified through ROC analysis a VTVRR > 11.46 % as the best cut-off to determine post-HTP 6-month survival outcome (AUC = 0.733; sensitivity = 70.0 %, specificity = 83.3 %). This cut-off was significantly associated with longer overall survival (HR = 0.372; P  = 0.039). According to RECIST1.1 and Choi criteria, good responders to EUS-HTP were 60 % and 46.7 %, respectively. Good responders according to Choi, but not to RECIST1.1, had longer survival (HR = 0.407; P  = 0.04). Conclusions  EUS-HTP induces a significant 1-month VTVRR. This effect is assessed accurately by evaluation of necrosis and tumor volumes. Use of VTVRR and Choi criteria, but not RECIST 1.1 criteria, might identify patients who could benefit clinically from EUS-HTP.

Standardization of a Radiofrequency Ablation Tool in an Ex-Vivo Porcine Liver Model

(1) Background: Preclinical and clinical data about a novel radiofrequency ablation (RFA) system (STARmed Co, Ltd.; Koyang, Korea) designed to be used under endoscopic ultrasound (EUS) control for pancreatic lesion ablation, are limited, obtained with non-standardized procedures and heterogeneous results. The aim of this study is to standardize the RFA procedure of this system in order to define the optimal ablation power and time. (2) Methods: RFA was performed on an ex-vivo porcine liver at different powers (40, 30, 20, 10 Watts (W)) and times (1, 3, 5, 7, 15 min) with a 1-centimeter monopolar electrode (perfused by chilled solution) positioned on the distal tip of a 19-Gauge needle. A blinded expert pathologist histologically analyzed each ablation area. (3) Results: The size of the total macroscopic ablated area was negatively correlated with ablation power (R −0.74): the largest was obtained at 10 W (p = 4.7 × 10−4) for longer times (R 0.92; p = 8.9 × 10−8). Central histologic coagulative necrosis did not differ among ablation settings (mean size 3.25 mm). External “parenchymal hypochromia” or “diaphanization” resulted the widest at 10 W, for longer times (R 0.8, p = 3.6 × 10−4). (4) Conclusions: The RFA system can produce small sizes of coagulative necrosis, regardless of the setting. Larger areas of diaphanization surrounding the necrosis can be produced at lower powers for longer times.

A Comprehensive Narrative Review on the Evolving Role of Endoscopic Ultrasound in Focal Solid Liver Lesions Diagnosis and Management

The implications of endoscopic ultrasound (EUS) have expanded considerably in recent years to cover more fields in invasive gastroenterology practice, as both an investigative and therapeutic modality. The utility of EUS in the diagnosis and management of focal liver lesions has gained a special attractiveness recently. The EUS probe proximity to the liver and its excellent spatial resolution enables real-time images coupled with several enhancement techniques, such as contrast-enhanced (CE) EUS. Aside from its notable capability to execute targeted biopsies and therapeutic interventions, EUS has developed into a hopeful therapeutic tool for the management of solid liver lesions. Herein, we provide a comprehensive state-of-the-art review on the efficacy and safety of EUS in the diagnosis and management of focal solid liver lesions. Medline/PubMed and Embase database searches were conducted by two separate authors (T.K. and W.S.), all relevant studies were assessed, and relevant data was extracted and fully reported. EUS-guided diagnosis of focal liver lesions by sonographic morphologic appearance and cytological and histopathological finding of biopsies obtained via fine needle aspiration/biopsy have been shown to significantly improve the diagnosis of solid liver lesions compared with traditional imaging tools. Similarly, EUS-guided treatment has been shown to consistently have excellent technical success, high efficacy, and minor adverse events. The evolving valuable evidences of EUS utility might satisfy the unmet need of optimizing management of focal solid liver lesions.

Systematic review of endoscopy ultrasound-guided thermal ablation treatment for pancreatic cancer

The development of curvilinear-array EUS and EUS-guided fine-needle aspiration (EUS-FNA) has led these approaches to become interventional procedures rather than purely diagnostic, as a minimally invasive antitumor therapeutic alternative to radiological and surgical treatments. The possibility to accurately position needle devices and to reach a deep target like the pancreas gland under real-time imaging guidance has expanded the use of EUS to ablate tumors. Currently, a variety of probes specifically designed for EUS ablation are available, including radiofrequency, hybrid cryothermal ablation (combining radiofrequency with cryotechnology), photodynamic therapy, and laser ablation. To date, several studies have demonstrated the safety and feasibility of these ablation techniques in the pancreatic setting, but only a few small series on pancreatic thermal ablation under EUS guidance are available. EUS-guided thermal ablation is primarily used for pancreatic cancer. It is well suited to this disease because of its superior anatomical access compared with other imaging modalities and the dismal prognosis despite improvements in chemoradiotherapy and surgery in the management of pancreatic cancer. Other targets are pancreatic neuroendocrine tumors and pancreatic cystic neoplasms, which are curable by surgical resection, but some patients are poor surgical candidates or prefer conservative management. This is a literature review of previously published clinical studies on EUS-guided thermal ablative therapies. Data on the long-term efficacy of EUS-guided antitumor thermal ablation therapy and large prospective randomized studies are still needed to confirm the real clinical benefits of these techniques for the management of pancreatic neoplasms.

The role of EUS in diagnosis and treatment of liver disorders

Background and aim  Transabdominal ultrasound (US), computed tomographic scanning (CT) and magnetic resonance imaging (MRI) are established diagnostic tools for liver diseases. Percutaneous transhepatic cholangiography is used to perform hepatic interventional procedures including biopsy, biliary drainage procedures, and radiofrequency ablation. Despite their widespread use, these techniques have limitations. Endoscopic ultrasound (EUS), a tool that has proven useful for evaluating the mediastinum, esophagus, stomach, pancreas, and biliary tract, has an expanding role in the field of hepatology complementing the traditional investigational modalities. This review aimed to assess the current scientific evidence regarding diagnostic and therapeutic applications of EUS for hepatic diseases.

Endoscopic Ultrasound-Guided Ablation of Liver Tumors

"Endoscopic ultrasound (EUS)-guided ablative therapies have advanced significantly and have led to experimental applications in locations that have been difficult to image and/or reach with percutaneous approaches, such as the caudate and left lobe of the liver. EUS-guided treatments of the liver are under development. The literature has shown that many percutaneous ablative techniques are readily adaptable for EUS. In this review, the authors discuss the current developments on EUS-guided ablation of liver tumors, including injection of sclerosants, thermal therapy, and EUS-guided portal injection of chemotherapy."

EUS dating with laser ablation against the caudate lobe or left liver tumors: a win-win proposition?

Endoscopic ultrasound (EUS) have been not only a diagnostic tool, but also available in interventional therapy, which often previously needed surgical approaches to achieve. The study aimed to evaluate the effectiveness and safety of EUS-guided Nd:YAG laser ablation in unresectable tumors of the caudate lobe and left liver. We discussed ten cases of the caudate lobe and left liver tumors underwent laser ablation with EUS guidance. And we also have reviewed previous publication of EUS-guided thermal ablation for liver tumors in several decade years. EUS-guided Nd:YAG laser ablation (LA) of these tumors were successfully completed in ten patients, who had favourable prognosis with no complications in two-month follow-up. Based on our early observations, this suggested that EUS-guided LA might be technically feasible in selected patients with tumors of the caudate lobe and left liver. However, the safety of this technique need to be further confirmed in the future and if possible larger, prospective trials.

Endoscopic ultrasonography-guided tumor ablation

Real-time guidance of needle advancement has transformed endoscopic ultrasound (EUS) from a diagnostic to an interventional procedure. EUS-guided fine-needle puncture has application in various interventional procedures (drainage of pseudocyst, biliary intervention, and injection of drugs). Celiac plexus or ganglion neurolysis for pain control is the major current EUS-guided fine-needle injection procedure. Feasibility and safety to accurately position needle devices and/or inject under real-time EUS imaging with precise delivery of interventional agent have expanded the use of EUS to ablate tumors. These include radiofrequency ablation, or delivery of fiducial markers, potential antitumor agents, or radioactive seeds, in the cancer mass. Minimally invasive EUS-guided antitumor therapy is primarily used for pancreatic cancer because of better anatomic access (vs other imaging modality) and the dismal prognosis (despite improvements in surgery and chemoradiation). Also, the response to parenteral chemotherapy in pancreatic cancer is poor because of suboptimal drug delivery resulting from hypovascularity and abundant desmoplasia. Other targets for EUS-guided tumor ablation are pancreatic neuroendocrine tumor and pancreatic cyst lesion, which are less aggressive and curable by resection. However, patients non-eligible for surgery may benefit from local EUS-guided ablation.

Endoscopy-guided ablation of pancreatic lesions: Technical possibilities and clinical outlook

Endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP)-guided ablation procedures are emerging as a minimally invasive therapeutic alternative to radiological and surgical treatments for locally advanced pancreatic cancer (LAPC), pancreatic neuroendocrine tumours (PNETs), and pancreatic cystic lesions (PCLs). The advantages of treatment under endoscopic control are the real-time imaging guidance and the possibility to reach a deep target like the pancreas. Currently, radiofrequency probes specifically designed for ERCP or EUS ablation are available as well as hybrid cryotherm probe combining radiofrequency with cryotechnology. To date, many reports and case series have confirmed the safety and feasibility of that kind of ablation technique in the pancreatic setting. Moreover, EUS-guided fine-needle injection is emerging as a method to deliver ablative and anti-tumoral agents inside the tumuor. Ethanol injection has been proposed mostly for the treatment of PCLs and for symptomatic functioning PNETs, and the use of gemcitabine and paclitaxel is also interesting in this setting. EUS-guided injection of chemical or biological agents including mixed lymphocyte culture, oncolytic viruses, and immature dendritic cells has been investigated for the treatment of LAPC. Data on the long-term efficacy of these approaches, and large prospective randomized studies are needed to confirm the real clinical benefits of these techniques for the management of pancreatic lesions.

Thermal ablation of pancreatic cyst with a prototype endoscopic ultrasound capable radiofrequency needle device: A pilot feasibility study

BACKGROUND AND OBJECTIVES

Pancreatic cysts are evaluated by endoscopic ultrasound and fine needle aspiration (EUS). The only accepted treatment is pancreatectomy, which is associated with morbidity and mortality. This study evaluated the optimal thermal dosimetry of a novel radiofrequency ablation device using a standard electrosurgical unit in ex vivo cyst models.

METHODS

A modified EUS 22-gauge monopolar needle prototype with a tip electrode connected to a standard electrosurgical unit (Erbe USA, Marietta, GA, USA) was used to induce a subboiling point temperature. A cyst model was created using 2-cm sections of porcine small intestine ligated and filled with saline. After ablation, the cyst models were prepared for pathological evaluation. The epithelial layers were measured in at least two different sites with a micrometer and compared with the corresponding control sample.

RESULTS

Thirty-two cyst models were ablated with maximum temperatures of 50°C, 60°C, 90°C, and 97°C in 8, 11, 11, and 2 cysts, respectively. Longer ablation times were required to induce higher temperatures. A trend in the reduction in thickness of the measured layers was observed after exposure to higher temperatures. A temperature over 50°C was required for the ablation of the muscularis, submucosa, and villi, and over 60°C was required to ablate the mucosal crypts.

CONCLUSIONS

In a preclinical model, a novel radiofrequency EUS-capable needle connected to a standard electrosurgical unit using standard low-voltage coagulation provided ablation in a temperature-dependent fashion with a threshold of at least 60°C and a safe cyst margin below 97°C. This potentially will allow low-cost, convenient cyst ablation.

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

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

[Endoscopic Ultrasound-guided Local Therapy of Pancreatic Tumors]

The development of curvilinear EUS has enabled EUS-guided fine-needle aspiration of intra-abdominal mass lesions. With the introduction of interventional EUS, this technology has undergone several modifications in order to be applied to clinical medicine. One of the potential uses of interventional EUS is the EUS-guided local therapy of pancreatic tumors. Various treatment modalities such as fine-needle injection, radiofrequency ablation, photodynamic therapy, laser ablation, and brachytherapy have been tried under EUS guidance. Some of these modalities are being applied clinically. These methods for EUS-guided local therapy of pancreatic tumors will be reviewed in this article.

Learning models for endoscopic ultrasonography in gastrointestinal endoscopy

Endoscopic ultrasonography (EUS) has become a useful diagnostic and therapeutic modality in gastrointestinal endoscopy. However, EUS requires additional training since it requires simultaneous endoscopic manipulation and ultrasonographic interpretation. Obtaining adequate EUS training can be challenging since EUS is highly operator-dependent and training on actual patients can be associated with an increased risk of complications including inaccurate diagnosis. Therefore, several models have been developed to help facilitate training of EUS. The models currently available for EUS training include computer-based simulators, phantoms, ex vivo models, and live animal models. Although each model has its own merits and limitations, the value of these different models is rather complementary than competitive. However, there is a lack of objective data regarding the efficacy of each model with recommendations on the use of various training models based on expert opinion only. Therefore, objective studies evaluating the efficacy of various EUS training models on technical and clinical outcomes are still needed.

Endoscopic Ultrasound-Guided Treatment beyond Drainage: Hemostasis, Anastomosis, and Others

Since the introduction of endoscopic ultrasound (EUS) in the 1990s, it has evolved from a primarily diagnostic modality into an instrument that can be used in various therapeutic interventions. EUS-guided fine-needle injection was initially described for celiac plexus neurolysis. By using the fundamentals of this method, drainage techniques emerged for the biliary and pancreatic ducts, fluid collections, and abscesses. More recently, EUS has been used for ablative techniques and injection therapies for patients with for gastrointestinal malignancies. As the search for minimally invasive techniques continued, EUS-guided hemostasis methods have also been described. The technical advances in EUS-guided therapies may appear to be limitless; however, in many instances, these procedures have been described only in small case series. More data are required to determine the efficacy and safety of these techniques, and new accessories will be needed to facilitate their implementation into practice.

A comparison of internally water-perfused and cryogenically cooled monopolar and bipolar radiofrequency applicators in ex vivo liver samples

RATIONALE AND OBJECTIVES

To evaluate the ex vivo ablation zones created in hepatic tissue using monopolar and bipolar gas- and water-cooled radiofrequency (RF) applicators.

MATERIALS AND METHODS

RF ablations were performed on ex vivo bovine liver tissue using closed circuit water-cooled and closed circuit cryogenically cooled (via CO₂ enthalpy) 15-ga linear-needle applicators. Both monopolar and bipolar electrode applicators were used, with the electric current administered ranging in 50-mA increments from 1100 to 1300 mA for the monopolar case, and from 500 to 700 mA for the bipolar case. Total ablation time was 15 minutes. Six tissue samples were ablated per setting. The ablated volumes were assumed to have a three-dimensional ellipsoid shape, with one long major axis and two smaller minor axes. Gross histology was used to measure the dimensions of the ablated regions to quantify the ablated volume, the dimensions of the axis, and the ratio between the long axis and the smallest minor axis, which was termed the ellipticity index.

RESULTS

The gas-cooled monopolar applicator achieved the largest short-axis ablation diameter (4.05 ± 0.4 cm), followed by the water-cooled monopolar applicator (3.18 ± 0.29 cm). With the bipolar applicator, the gas-cooled applicators also achieved larger short-axis ablation diameters (3.02 ± 0.15 cm) than the water-cooled applicators (2.72 ± 0.29 cm). The gas-cooled monopolar applicator also provided the largest ablation volume (42.7 ± 10.7 mL) and the most spherically shaped lesions (ellipticity index: 1.21 ± 0.10). Lesion size increased with injected current up to a threshold current of 1200/1250 mA (monopolar water-/gas-cooled) and 600/650 mA (bipolar water-/gas-cooled), but dropped at greater values.

CONCLUSIONS

Gas-cooled monopolar applicators were superior to the other tested applicators in terms of both volume and sphericity of the ablation zone.

Interventional endoscopic ultrasonography

OPINION STATEMENT

Endoscopic ultrasound (EUS) is not only a diagnostic tool but also an interventional and therapeutic procedure. Indeed, in addition to tissue acquisition, it can also drain fluid collections adjacent to the gastrointestinal tract, provide access to biliary and pancreatic ducts, biliary, pancreatic, and gallbladder drainage, pancreatic cyst ablation, and, finally, provide anti-tumoral treatments and interventional vascular procedures. Although several improvements have been made in the last decade, the full potential of interventional EUS is yet to be completely explored. Future areas of research are the development of dedicated tools and accessories, the standardization of the interventional procedures, and the widening of the use of EUS, while increasing the expertise worldwide. In addition, more data, based on well-performed, possibly randomized clinical trials, are needed to accurately determine the risks and long-term outcomes of these interventions. We firmly believe that interventional EUS can play a pivotal role in anti-tumor treatments, by the fine-needle injection of anti-tumoral agents, tumor ablation, and assisting radiation treatment with gold fiducial placement and the implantation of intralesional seeds. The goal of the near future will be to offer targeted therapy and monitoring of tumor treatment response in a more biologically driven manner than has been available in the past. Interventional EUS will be an essential part of the multidisciplinary approach to cancer treatment.

Endoscopic ultrasound-guided oncologic therapy for pancreatic cancer

Since the development of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in the early 1990s, its application has been extended to various diseases. For pancreatic cancer, EUS-FNA can obtain specimens from the tumor itself with fewer complications than other methods. Interventional EUS enables various therapeutic options: local ablation, brachytherapy, placement of fiducial markers for radiotherapy, and direct injection of antitumor agents into cancer. This paper will focus on EUS-guided oncologic therapy for pancreatic cancer.

Feasibility and safety of EUS-guided cryothermal ablation in patients with locally advanced pancreatic cancer

BACKGROUND

New therapies are needed for pancreatic cancer.

OBJECTIVE

To determine the feasibility and safety of a new endoscopic treatment. Secondary endpoints were to determine effects on tumor growth measured with CT scan and to find the overall survival.

DESIGN

A cohort study of patients with local progression of advanced pancreatic adenocarcinoma after neoadjuvant therapy. The cryotherm probe (CTP), a flexible bipolar device that combines radiofrequency with cryogenic cooling, was used under EUS guidance.

SETTING

San Raffaele Hospital, Milan, Italy; University Medical Center, Hamburg-Eppendorf, Germany.

PATIENTS

A total of 22 patients (male/female 11/11; mean age 61.9 years) were enrolled from September 2009 to May 2011.

INTERVENTION

Radiofrequency heating: 18 W; pressure for cooling: 650 psi (Pounds per Square Inch); application time: depending on tumor size.

MAIN OUTCOME MEASUREMENTS

Feasibility was evaluated during the procedure. A clinical and radiologic follow-up was planned.

RESULTS

The CTP was successfully applied in 16 patients (72.8%); in 6 it was not possible because of stiffness of the GI wall and of the tumor. Amylase arose in 3 of 16 patients; none had clinical signs of pancreatitis. Late complications arose in 4 cases: 3 were mostly related to tumor progression. Median postablation survival time was 6 months. A CT scan was performed in all patients, but only in 6 of 16 was it possible to clearly define the tumor margins after ablation. In these patients, the tumor appeared smaller compared with the initial mass (P = .07).

LIMITATIONS

Small sample of patients, difficulty of objectifying the size of the ablated zone by CT scan.

CONCLUSION

EUS-guided CTP ablation is feasible and safe. Further investigations are needed to demonstrate progression-free survival and local control.

Endoscopic ultrasonography-guided tumor ablation

With the introduction of curvilinear endosonoscopes, endoscopic ultrasonography (EUS) has achieved the role of a therapeutic modality as well as diagnostic procedure. EUS-guided tumor ablation is one such therapeutic modality. Various techniques of EUS-guided tumor ablation have been described, including radiofrequency ablation, photodynamic therapy, laser ablation, and ethanol injection. Most of the currently described techniques are experimental. Development and continuous improvement of devices, as well as establishment of indications for EUS-guided tumor ablations, are mandatory.

Interventional endoscopic ultrasonography for pancreatic cancer

Endoscopic ultrasonography (EUS) represents the combination of endoscopy and intraluminal ultrasonography. This allows use of a high-frequency transducer (5-20 MHz) that, due to the short distance to the target lesion, provides ultrasonographic images of higher resolution than those obtained from other imaging modalities, including multiple-detector-row-computed tomography, magnetic resonance imaging, and positron emission tomography. EUS is now a widely accepted modality for diagnosing pancreatic diseases. However, the most important limitation of EUS has been the lack of specificity in differentiating between benign and malignant changes. In 1992, EUS-guided fine needle aspiration (FNA) of lesions in the pancreas head was introduced into clinical practice, using a curved linear-array echoendoscope. Since then, EUS has evolved from EUS imaging to EUS-FNA and wider applications. Interventional EUS for pancreatic cancer includes EUS-FNA, EUS-guided fine needle injection, EUS-guided biliary drainage and anastomosis, EUS-guided celiac neurolysis, radiofrequency ablation, brachytherapy, and delivery of a growing number of anti-tumor agents. This review focuses on interventional EUS, including EUS-FNA and therapeutic EUS for pancreatic cancer.

US-guided application of a new hybrid probe in human pancreatic adenocarcinoma: an ex vivo study

BACKGROUND

Ablative therapies such as radiofrequency and cryotechnology are widely used in oncological intervention but not in the pancreatic field because of their high operative risks. A new flexible bipolar ablation device (Cryotherm probe [CTP]) was developed combining radiofrequency and cryotechnology.

OBJECTIVE

To evaluate the efficacy of the CTP in destroying neoplastic tissue of explanted pancreatic tumors of patients with pancreatic adenocarcinoma.

DESIGN

Ex vivo clinical study.

SETTING

Inpatient hospital setting.

PATIENTS

This study involved 16 explanted pancreatic tumors from 16 patients.

INTERVENTIONS

CTP application was performed on explanted pancreatic tumors. Anatomic specimens were divided into 4 groups; each group received a predefined application time of 120 to 600 seconds.

MAIN OUTCOME MEASUREMENTS

The coagulation diameter (short axis) perpendicular to the device's longitudinal axis was used as the primary outcome measure.

RESULTS

All pancreatic specimens showed histological signs of coagulative necrosis. There was a positive correlation between the short axis of the obtained necrosis and duration of application (r = 0.74).

LIMITATIONS

This study was an ex vivo study with all limitations typical of this kind of study.

CONCLUSIONS

The CTP is effective in destroying neoplastic pancreatic tissue, creating an ablation zone, the extent of which is related to the duration of application.

Interventional endoscopic ultrasound: Therapeutic capability and potential

The linear echoendoscope, introduced in the 1990s, opened the era of interventional endoscopic ultrasound (IEUS). The linear echoendoscope enabled EUS guided Fine Needle Aspiration (EUS-FNA) allowing the path of the needle to be traced during the puncture process. After EUS-FNA, other interventional procedures were introduced in clinical practice. Tissue acquisition was the first EUS-guided interventional procedure and its higher diagnostic quality has undoubtedly been established. After EUS-FNA, Celiac plexus neurolysis (CPN) and block (CPB), pancreatic pseudocyst drainage, abdominal and mediastinal collections/abscesses drainage, and in selected cases, pancreatic and biliary ductal system drainage, were introduced in clinical practice. EUS-guided fine needle injection with local delivery of antitumor agents is considered a promising modality. We have reviewed published data on EUS guided interventional procedures with the object of summarizing the diagnostic capability of endoscopic ultrasound and elaborates in detail its therapeutic capability and potential.

Role of endosonography in drainage of fluid collections and other NOTES procedures

Endosonography (EUS) has become the accepted procedure for drainage of pancreatic fluid collections in the past decade. EUS was shown to be safe and effective and it has been the first-line therapy for uncomplicated pseudocysts. Where walled-off pancreatic necrosis was originally thought to be a contraindication for endoscopic treatment, multiple case series have now shown that these fluid collections also can be treated endoscopically with low morbidity and mortality. Analogous to the treatment of pancreatic fluid collections, others, such as abscesses in the lower and upper abdomen, have also been treated successfully, although there is limited literature in this regard, EUS appears to be a useful technique in natural orifice transluminal endoscopic surgery (NOTES) procedures as well.