EUS-guided radiofrequency ablation in the pancreas: results in a porcine model

Endoscopic Ultrasound-Guided Radiofrequency Ablation for Pancreatic Adenocarcinoma: A Scoping Review with Meta-Analysis

Background: Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) has recently been proposed as an alternative treatment option for patients with unresectable pancreatic adenocarcinoma (uPDAC) or metastatic pancreatic adenocarcinoma (mPDAC). This review aims to evaluate the technical feasibility, safety, and clinical outcomes of EUS-RFA in treating PDAC, based on the available literature. Methods: Following the PRISMA-DTA guidelines, a comprehensive search of databases, including PubMed, Scopus, and the Cochrane Library, was conducted, focusing on studies reporting on EUS-RFA for PDAC. Articles involving human subjects diagnosed with PDAC and treated with EUS-RFA, written in English, and published up to 30 June 2024, were included. Key outcome measures such as technical success rate, adverse events, tumor response, and patient survival were extracted and analyzed. The review process involved title and abstract screening, followed by full-text review. A meta-analysis was performed for adverse event rates using a random-effects model. Results: We identified 11 studies according to our inclusion criteria, with a total of 137 patients with PDAC. Except for the initial experience with a lower technical success rate due to tumor-related stiffness, all subsequent studies reported a pooled success rate of 100%. Most studies referred to locally advanced or metastatic PDAC, while one reported EUS-RFA in resectable PDAC. A meta-analysis for adverse events was performed, indicating a pooled adverse event rate of 22.6% (95% confidence interval: 0.16-0.30), with the most common adverse event being mild abdominal pain. Severe complications were rare. One study reported a median progression-free survival (PFS) of 16.3 months. Overall survival and PFS were scarcely reported, with median overall survival ranging from 12 to 24 months, inferior to that of the standard approach for uPDAC consisting of neoadjuvant chemoradiotherapy followed by surgery. Conclusions: EUS-RFA is a technically feasible and safe procedure for treating uPDAC or mPDAC and is under investigation for use in resectable PDAC. Even though the short-term outcomes are encouraging, larger cohort studies are necessary to understand long-term efficacy and survival benefits, including progression-free survival.

Reducing the incidence of pancreatic cancer through radiofrequency ablation of mucinous cystic neoplasms: What is the evidence?

Pancreatic cystic lesions are mostly discovered incidentally during cross-sectional imaging for other indications. They range from benign cysts to premalignant lesions, posing a risk for development of pancreatic cancer. Surveillance of cysts with low-risk features and surgical resection of high-risk ones has been the standard of care. However, the lack of consensus between national society guidelines results in discordant management and follow-up. One of the upcoming therapeutic modalities for pancreatic cysts, including mucinous cystic neoplasms (MCN), is endoscopic ultrasound (EUS)-guided interventions, including injection of chemotherapeutic agents or EUS-guided radiofrequency ablation (EUS-RFA). EUS-RFA is emerging as a promising minimally invasive tool with the need for further investigation to understand its clinical utility. This review discusses the physiology, clinical studies, adverse events, and future perspectives of RFA for various pancreatic lesions, with particular regard with MCN.

Endoscopic-Ultrasound-Guided Radiofrequency Ablation for Pancreatic Tumors

Endoscopic ultrasound (EUS)-guided radiofrequency ablation (RFA) is a promising minimally invasive technique for the treatment of pancreatic lesions. This review first focuses on the technical aspects in EUS-RFA: the procedure typically employs EUS probes with integrated radiofrequency electrodes, enabling accurate targeting and ablation of pancreatic lesions. Different types of RFA devices, monopolar and bipolar energy delivery systems, are discussed, along with considerations for optimal ablation, including energy settings, procedure time, and pre- and post-procedural management. This paper presents a comprehensive literature review of EUS-RFA applied to both solid and cystic pancreatic lesions, including functioning and non-functioning pancreatic neuroendocrine tumors (pNETs), pancreatic cystic lesions (PCLs), pancreatic ductal adenocarcinoma (PDAC), and pancreatic metastases (PMs), discussing current evidence on safety, efficacy, clinical outcomes, and adverse events (AEs). EUS-RFA is an emerging technique with expanding potential for the treatment of both benign and malignant conditions; however, further studies are needed to better define patient selection criteria, assess long-term benefits, and establish definitive indications for its use.

Role of Endoscopic Ultrasound-Guided Radiofrequency Ablation in Pancreatic Lesions: Where Are We Now and What Does the Future Hold?

Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) has emerged as an effective and minimally invasive treatment for pancreatic lesions, particularly in patients at high surgical risk. Utilizing thermal energy, RFA induces the coagulative necrosis of the tissue and potentially triggers immunomodulation by releasing intracellular antigens. Numerous studies have confirmed the technical feasibility, safety, and efficacy of EUS-RFA in pancreatic neuroendocrine tumors and premalignant cystic lesions, with an acceptable profile of adverse events. The technique's potential immunomodulatory effects offer intriguing implications for the treatment of advanced pancreatic malignancies, encouraging further evaluation. This review paper aims to highlight the EUS-RFA principles, technology, and clinical applications in various pancreatic lesions and safety, and the future research directions.

EUS-guided radiofrequency ablation for pancreatic adenocarcinoma

BACKGROUND AND AIMS

Emerging data suggest neoadjuvant chemotherapy (NAC) for resectable pancreatic ductal adenocarcinoma (PDAC) is associated with improved survival. However, less than 40% of patients demonstrate a meaningful radiographic response to NAC. EUS-guided radiofrequency ablation (EUS-RFA) has emerged as a new modality to treat PDAC. We hypothesize that NAC plus EUS-RFA can be used in the management of resectable PDAC.

METHODS

This was a prospective review of PDAC patients meeting the criteria of resectable tumor anatomy who underwent NAC chemotherapy plus EUS-RFA followed by pancreatic resection. Radiographic imaging and perioperative and short-term outcomes were recorded. Surgical pathology specimens were analyzed for treatment response.

RESULTS

Three eligible patients with resectable PDAC received 4 months of NAC plus EUS-RFA. One month after completing NAC and EUS-RFA, all 3 patients underwent standard pancreaticoduodenectomy without adverse events. After a 6-week recovery, all patients completed 2 months of postoperative adjuvant chemotherapy.

CONCLUSIONS

In our institutional experience, this treatment protocol appears to be safe as patients tolerated the combination of chemotherapy and ablation. Patients underwent pancreatic resection with uneventful recovery. This novel neoadjuvant approach may provide a more effective alternative to chemotherapy alone.

EUS-Guided Radiofrequency Ablation Therapy for Pancreatic Neoplasia

Radiofrequency ablation (RFA) under endoscopic ultrasound (EUS) guidance has been developed and utilized over the last decade to provide the loco-regional treatment of solid and cystic pancreatic neoplastic lesions. The advantage of this approach relies on the close proximity of the EUS transducer to the target pancreatic lesion, which, coupled with the development of specifically designed RFA ablation devices, has made the procedure minimally invasive, with a clear reduction in adverse events as compared to the high morbidity of the surgical approach. EUS-RFA has been applied so far to pancreatic functional and non-functional neuroendocrine neoplasms, pancreatic ductal adenocarcinoma or metastases to the pancreas, and pancreatic neoplastic cysts. Excluding neuroendocrine tumors, for other indications, most of these procedures have been performed in patients who refused surgery or were at high surgical risk. More studies evaluating EUS-RFA in selected patients, not at surgical risk, are gradually becoming available and will pave the road to extend the indications for this therapeutic approach, also in association with other oncological therapies. The present manuscript will critically review the available evidence in the field of the EUS-guided RFA of solid and cystic pancreatic neoplasms.

Harnessing endoscopic ultrasound-guided radiofrequency ablation to reshape the pancreatic ductal adenocarcinoma microenvironment and elicit systemic immunomodulation

Pancreatic ductal adenocarcinoma (PDAC) is characterized by poor prognostics and substantial therapeutic challenges, with dismal survival rates. Tumor resistance in PDAC is primarily attributed to its fibrotic, hypoxic, and immune-suppressive tumor microenvironment (TME). Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA), an Food and Drug Administration (FDA)-approved minimally invasive technique for treating pancreatic cancer, disrupts tumors with heat and induces coagulative necrosis, releasing tumor antigens that may trigger a systemic immune response-the abscopal effect. We aim to elucidate the roles of EUS-RFA-mediated thermal and mechanical stress in enhancing anti-tumor immunity in PDAC. A comprehensive literature review focused on radiofrequency immunomodulation and immunotherapy in pancreatic tumors to understand the pathophysiological mechanisms of RFA and its effect on the TME, which could prevent recurrence and resistance. We reviewed clinical, preclinical, and in vitro studies on RFA mechanisms in pancreatic adenocarcinoma, discussing the unique immunomodulatory effects of EUS-RFA. Recent findings suggest that combining RFA with immune adjuvants enhances responses in pancreatic adenocarcinoma. EUS-RFA offers a dual benefit against PDAC by directly reducing tumor viability and indirectly enhancing anti-tumor immunity. Observations of neutrophil-mediated immunomodulation and programmed cell death ligand 1 (PD-L1) modulation support integrating EUS-RFA with targeted immunotherapies for managing pancreatic adenocarcinoma. Integrating EUS-RFA in PDAC treatment promises direct cytoreduction and synergistic effects with molecular targeted therapies. Prospective clinical trials are crucial to assess the efficacy of this combined approach in improving outcomes and survival rates in advanced PDAC cases.

Endoscopic loco-regional treatment in controlling pancreatic neuroendocrine tumors (PNETs) behavior: a case series and literature review

Pancreatic neuroendocrine tumors (PNETs) are considered rare pancreatic neoplasms, and it is a challenging disease entity due to its indolent behavior and is difficult to manage. Diagnostic challenge is usually found in the imaging-based approach, such as transabdominal ultrasound, abdominal CT scan, and abdominal MRI. Surgery is still the main key player in controlling the disease. The main problems in clinical practice are the early detection of small PNETs lesion and non-functional PNET (NF-PNET) cases. Most cases usually come with large tumor size or metastatic disease. Endoscopic ultrasound (EUS) has been well-known as the most sensitive tool for early detection of pancreatic malignancy. It has now also been developed for managing pancreatic cancer, such as tumor ablation therapy. We presented four variety of PNETs cases (one patient with non-functioning PNETs and three patients with functioning PNETs) who have been successfully treated with EUS-guided radiofrequency ablation (RFA) with good control of tumor growth during follow-up. One patient with a large-size insulinoma could have the tumor controlled gradually after several EUS-RFA sessions. No adverse events or major complications were observed during and after the EUS-RFA procedure. EUS has been shown as a promising tool not only for more accurate diagnosis but also for tumor growth control. However, it would need further comparison studies between EUS and surgical approaches to make a better treatment strategy.

Outcomes of endoscopic ultrasound-guided ablation and minimally invasive surgery in the treatment of pancreatic insulinoma: a systematic review and meta-analysis

Background and aims

Most pancreatic insulinomas can be treated by minimally invasive modalities. The aim of this meta-analysis was to assess the clinical outcomes of endoscopic ultrasound (EUS)-guided ablation and minimally invasive surgery (MIS) in the treatment of pancreatic insulinoma.

Materials and methods

Online databases were searched for relevant studies. The primary aim was to compare the rates of adverse events (AEs) and the secondary aims were to compare the clinical and technical success rates, length of hospital stays, and symptom recurrence rates between EUS and MIS approaches.

Results

Eight studies with 150 patients were identified that reported EUS-guided ablation outcomes, forming the EUS group, and 9 studies with 236 patients reported MIS outcomes, forming the MIS group. The pooled median age of the included patients in the EUS group was greater than that of the MIS group (64.06 vs. 44.98 years old, p < 0.001). Also, the technical success rate was significantly higher in the EUS group (100% vs. 96.6%, p = 0.025), while the clinical success was significantly higher (6%) in the MIS group (94% vs. 98.7%, p = 0.021). The AE rates (18.7% vs. 31.1%, p = 0.012) and severe AE rates (1.3% vs. 7.9%, p = 0.011) were significantly lower in the EUS group. The median length of hospital stay in the EUS group (2.68 days, 95% CI: 1.88-3.48, I2 = 60.3%) was significantly shorter than in the MIS group (7.40 days, 95% CI: 6.22-8.58, I2 = 42.2%, p < 0.001). The recurrence rate was significantly higher in the EUS group (15.3% vs. 1.3%, p < 0.001).

Conclusions

EUS-guided ablation is associated with a lower AE rate and a shorter length of hospital stay, but a higher recurrence rate for the treatment of insulinoma compared with MIS. The EUS approach may be an alternative, even first-line, treatment for poor surgery candidates.

Comparative efficacies and safeties of cylindrical interstitial laser ablation and radiofrequency ablation on swine pancreas

Laser ablation (LA) has been evaluated for the minimally invasive thermal treatment of various cancers, but conventional unidirectional endoscopic ultrasound (EUS)-guided LA has limitations. Therefore, we developed a cylindrical laser diffuser to overcome the limitations of unidirectional EUS-guided LA. The purpose of this study was to compare the efficacies and safeties of EUS-guided LA using a novel cylindrical laser diffuser and radiofrequency ablation (RFA) in vivo in swine pancreas. EUS-guided RFA (15 W, 30 s, 450 J) and cylindrical interstitial LA (CILA) (5 W, 90 s, 450 J) were applied to normal pancreatic tissue in six anesthetized pigs (three per group). Laboratory tests were performed at baseline, immediately after ablation (day 0), and 2 days after procedures (day 2). Two days after procedures, all pigs were sacrificed, and histopathological safety and efficacy assessments were performed. Technically, EUS-guided RFA and CILA were performed successfully in all cases. No major complications, including perforation or acute pancreatitis, occurred during the experiment in either group. All animals remained in excellent condition throughout the experimental period, and laboratory tests provided no evidence of a major complication. Average necrotic volumes in the RFA and CILA groups were 424.2 mm3 and 3747.4 mm3, respectively, and average necrotic volume was significantly larger in CILA group (p < 0.001). EUS-guided RFA and CILA had acceptable safety profiles in the normal swine pancreas model. Our findings indicate EUS-guided CILA has potential for the effective local treatment of pancreatic cancer as an alternative to EUS-guided RFA.

Endoscopic ultrasound-guided radiofrequency ablation of pancreatic insulinoma: a state of the art review

INTRODUCTION

Insulinomas are the most common functional pancreatic neuroendocrine tumors (PNETs) that lead to incapacitating hypoglycemia. Guidelines recommend surgical resection as the mainstay of management. However, surgery is fraught with complications, causing significant peri/post-operative morbidity. Since insulinomas are usually benign, solitary, small (<2 cm), and do not need lymphadenectomy, hence, in this regard, endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is now being increasingly performed, to circumvent these adverse events and impairment of pancreatic function.

AREAS COVERED

A comprehensive literature search was undertaken across various databases (PubMed/MEDLINE, Embase, Scopus), with no language restriction, for relevant articles (case series, reviews, case reports) pertaining to EUS-RFA for insulinoma and PNETs, till October 2023. In this review, we have explicated the role of EUS-RFA for insulinoma management, detailing thoroughly its mechanism of action, EUS-RFA devices with data on its safety and efficacy, and an algorithmic approach for its management.

EXPERT OPINION

EUS-RFA is being advocated as a 'mini-invasive' option with the potential to replace surgery as a first-line approach for benign, sporadic, solitary, and small (<2 cm) insulinomas. Under real-time guidance, EUS-RFA has immense precision, is safe, predictable, with acceptable safety profile. Presently, it is being frequently performed for high-risk or inoperable candidates. Current need-of-the-hour is a randomized controlled trial to substantiate its role in the therapeutic algorithm for insulinoma management.

EUS-guided radiofrequency ablation plus chemotherapy versus chemotherapy alone for pancreatic cancer (ERAP): An observational open-label pilot study

Background

No study has compared EUS-guided radiofrequency ablation (EUS-RFA) plus systemic chemotherapy (CMT) with CMT alone for unresectable pancreatic ductal adenocarcinoma.

Methods

This study compared the results of treatment in patients receiving EUS-RFA plus concomitant CMT (group A; n = 14) with those receiving CMT (group B; n = 14) as a pilot study.

Results

From July 2017 to August 2018, 4 and 2 patients from groups A and B, respectively, withdrew from the study because of progression of the disease. In total, 10 and 12 patients from groups A and B, respectively, completed the study. All 30 EUS-RFA procedures were successful. Mean maximal tumor diameter before treatment of group A (n = 10) versus B (n = 12) was 62.2 ± 21.0 versus 50.5 ± 22.0 mm, respectively (P = not significant). After treatment, no statistically significant difference in mean maximal tumor diameter was found between both groups. However, in group B, mean maximal tumor diameter was significantly increased from 50.5 ± 22.0 to 56.3 ± 18.7 mm, respectively (P = 0.017). Tumor necrosis occurred in group A versus B at 10 of 10 (100%) versus 6 of 12 (50%) patients, respectively (P = 0.014). After treatment, group A patients could reduce the mean narcotic pain drug dosage at 26.5 mg of morphine equivalent per day (from 63.6 to 37.1 mg, P = 0.022), whereas group B patients could not reduce the dosage of pain-controlled medication. No statistically significant difference in 6-month mortality rate was found. In group A, 1 procedure-related nonsevere adverse event (n = 1 of 30 [3.3%]) occurred in 1 patient (n = 1 of 14 [7.1%]).

Conclusions

In this study, the mean tumor diameter of group B was significantly increased after the treatment. Group A had a significantly higher rate of necrosis of tumor and required less narcotic.

Safety and efficacy of endoscopic ultrasound-guided radiofrequency ablation for pancreatic insulinoma: A single-center experience

BACKGROUND/OBJECTIVES

Insulinomas are rare, functioning pancreatic neuroendocrine neoplasms (pNEN), whose gold standard therapy is surgical resection. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is a recent technique that has emerged as a minimally invasive therapeutic option for patients with pancreatic lesions not eligible for surgery. In this study, we aimed to describe a series of patients with unresectable pancreatic insulinoma treated with EUS-RFA.

METHODS

This is a single-center, retrospective study including all consecutive patients with functioning pancreatic insulinoma undergoing EUS-RFA for surgical unfitness or surgery refusal, between March 2017 and September 2021. Technical success (i.e., complete mass ablation), adverse event rate and severity, clinical and radiologic outcomes (i.e., symptom remission with a normal concentration of blood glucose, and the presence of intralesional necrosis), and post-procedural follow-up were assessed.

RESULTS

A total of 10 patients (mean age: 67.1 ± 10.1years; F:M 7:3) were included. The mean size of insulinoma was 11.9 ± 3.3 mm. Technical success and clinical remission were achieved in 100% of patients. Only one (10%) patient was successfully treated with two RFA sessions. Two procedure-related early adverse events occurred, including two (20%) cases of mild abdominal pain. No major complications were observed. The complete radiologic response within 3 months after EUS-RFA was observed in all patients (100%). After a median follow-up of 19.5 (range12-59) months, symptom remission and persistent euglycemia were assessed in all the patients.

CONCLUSIONS

Data from this case series suggest that EUS-RFA is a feasible and safe therapeutic approach for pancreatic insulinomas in patients unwilling or unable to undergo surgery with medium-term efficacy.

Role of Therapeutic Endoscopic Ultrasound in Management of Pancreatic Cancer: An Endoscopic Oncologist Perspective

Pancreatic cancer is a highly lethal disease with an aggressive clinical course. Patients with pancreatic cancer are usually asymptomatic until significant progression of their disease. Additionally, there are no effective screening guidelines for pancreatic cancer in the general population. This leads to a delay in diagnosis and treatment, resulting in poor clinical outcomes and low survival rates. Endoscopic Ultrasound (EUS) is an indispensable tool for the diagnosis and staging of pancreatic cancer. In the modern era, with exponential advancements in technology and device innovation, EUS is also being increasingly used in a variety of therapeutic interventions. In the context of pancreatic cancer where therapies are limited due to the advanced stage of the disease at diagnosis, EUS-guided interventions offer new and innovative options. Moreover, due to their minimally invasive nature and ability to provide real-time images for tumor localization and therapy, they are associated with fewer complication rates compared to conventional open and laparoscopic approaches. In this article, we detail the most current and important therapeutic applications of EUS for pancreatic cancer, namely EUS-guided Fine Needle Injections, EUS-guided Radiotherapy, and EUS-guided Ablations. Furthermore, we also discuss the feasibility and safety profile of each intervention in patients with pancreatic cancer to provide gastrointestinal medical oncologists, radiation and surgical oncologists, and therapeutic endoscopists with valuable information to facilitate patient discussions and aid in the complex decision-making process.

Approaching Small Neuroendocrine Tumors with Radiofrequency Ablation

In recent years, small pancreatic neuroendocrine tumors (pNETs) have shown a dramatic increase in terms of incidence and prevalence, and endoscopic ultrasound (EUS) radiofrequency ablation (RFA) is one potential method to treat the disease in selected patients. As well as the heterogeneity of pNET histology, the studies reported in the literature on EUS-RFA procedures for pNETs are heterogeneous in terms of ablation settings (particularly ablation powers), radiological controls, and radiological indications. The aim of this review is to report the current reported experience in EUS-RFA of small pNETs to help formulate the procedure indications and ablation settings. Another aim is to evaluate the timing and the modality of the radiological surveillance after the ablation. Moreover, new studies on large-scale series are needed in terms of the safety and long-term oncological efficacy of RFA on these small lesions.

Ex-vivo investigation of radiofrequency ablation in pancreatic adenocarcinoma after neoadjuvant chemotherapy

OBJECTIVE

Endoscopic ultrasound (US)-guided radiofrequency ablation (RFA) has been investigated for pancreatic ductal adenocarcinoma (PDAC) but studies are limited and heterogeneous. Computed tomography (CT) scan features may predict RFA response after chemotherapy but their role is unexplored. The primary aim was to investigate the efficacy of ex-vivo application of a dedicated RFA system at three power on surgically resected PDAC in patients who underwent neoadjuvant chemotherapy. The secondary aim was to explore the association between pre-treatment CT-based quantitative features and RFA response.

METHODS

Fifteen ex-vivo PDAC samples were treated by RFA under US control at three power groups (10, 30, and 50 W). Short axis necrosis diameter was measured by two expert blinded pathologists as the primary outcome. Two radiologists independently reviewed preoperative CT images.

RESULTS

Eighty percent of specimens showed coagulative necrosis consisting of few millimeters: 5.7 ± 3.9 mm at 10 W, 3.7 ± 2.2 mm at 30 W, and 3.5 ± 2.4 mm at 50 W (p = 0.3), without a significant correlation between power setting and mean necrosis short axis (rho = -0.28; p = 0.30). Good agreement was seen between pathologists (k = 0.76; 95% confidence interval 0.55-0.98). Logistic regression analysis did not show associations between CT features and RFA response.

CONCLUSIONS

RFA causes histologically evident damage with coagulative necrosis of a few millimeters in 80% of ex-vivo PDAC samples after chemotherapy and no clinical or pre-operative CT features can predict efficacy. Power settings do not correlate with the histological ablation area. These results are of relevance when employing RFA in vivo and planning clinical trials on its role in PDAC patients.

Impact of endoscopic ultrasound-guided radiofrequency ablation in managing pancreatic malignancy

Pancreatic malignancy is still the most lethal gastrointestinal malignancy. It has a very poor prognosis with low survival rate. Surgery is still the main treatment option for pancreatic malignancy. Most patients already have locally advanced and even late stage disease due to non-specific abdominal symptoms. Even though some cases are still suitable for surgical treatment, due to its aggressiveness adjuvant chemotherapy is becoming the standard treatment for controlling the disease. Radiofrequency ablation (RFA) is a thermal therapy that has been used as one of the standard treatments for liver malignancy. It can also be performed intraoperatively. There are several reports on percutaneous RFA treatment for pancreatic malignancy using transabdominal ultrasound and guided by computed tomography scan. However, due to its anatomical location and the risk of high radiation exposure, these methods seem to be very limited. Endoscopic ultrasound (EUS) has been widely used for pancreatic abnormality evaluation due to its ability to detect more accurately, especially small pancreatic lesions, compared to other imaging modalities. By the EUS approach, it is easier to achieve good visualization of tumor ablation and necrosis as the echoendoscope position is closer to the tumor area. Based on studies and a recent meta-analysis, EUS-guided RFA is a promising treatment approach for most pancreatic malignancy cases, but most studies only collected data from a small sample size. Larger studies are needed before clinical recommendations can be made.

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.

A Review on Endoscopic Ultrasound-Guided Radiofrequency Ablation (EUS-RFA) of Pancreatic Lesions

The morbidity associated with pancreatectomies limits surgical options for high-risk patients with pancreatic neoplasms that warrant resection. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) offers a minimally invasive and potentially definitive means to treat pancreatic neuroendocrine tumors and precancerous pancreatic cystic lesions. In addition, EUS-RFA may play a role in the treatment and palliation of non-surgical cases of pancreatic adenocarcinoma. The efficacy of RFA appears to be further enhanced by systemic immunomodulatory effects. Here, we review current studies on the developing role of EUS-RFA in these pancreatic pathologies.

Endoscopic ultrasound guided radiofrequency ablation for pancreatic tumors: A critical review focusing on safety, efficacy and controversies

The role of endoscopic ultrasound (EUS) in the last two decades has shifted from a diagnostic tool to an important therapeutic tool treating mainly pancreato-biliary disorders. In recent years, its applications for treating pancreatic diseases have broadened, including the implementation of radiofrequency ablation (RFA), which has been traditionally used for treating solid tumors. In this critical in-depth review, we summarized all the papers throughout the literature regarding EUS-RFA for pancreatic neuroendocrine neoplasms, adenocarcinoma, and pancreatic cystic lesions. Overall, for pancreatic neuroendocrine neoplasms we identified 16 papers that reported 96 patients who underwent EUS-RFA, with acceptable adverse events that were rated mild to moderate and a high complete radiological resolution rate of 90%. For pancreatic adenocarcinoma, we identified 8 papers with 121 patients. Adverse events occurred in 13% of patients, mostly rated mild. However, no clear survival benefit was demonstrated. For pancreatic cystic lesions, we identified 4 papers with 38 patients. The adverse events were mostly mild and occurred in 9.1% of patients, and complete or partial radiological resolution of the cysts was reported in 36.8%. Notably, the procedure was technically feasible for most of the patients. Nevertheless, a long road remains before this technique finds its definite place in guidelines due to several controversies. EUS-RFA for pancreatic tumors seems to be safe and effective, especially for pancreatic neuroendocrine neoplasms, but multicenter prospective trials are needed to consider this treatment as a gold standard.

Endoscopic ultrasound-guided radiofrequency ablation of premalignant pancreatic-cystic neoplasms and neuroendocrine tumors: prospective study

BACKGROUND

Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is a developing therapeutic approach for premalignant pancreatic-cystic neoplasms (PCNs) and small pancreatic neuroendocrine tumors (PNETs). The safety and efficacy of pancreatic EUS-RFA were previously reported in small series. Herein we report our initial experience with RFA of PCNs and small PNETs.

METHODS

This is a prospective single-center study including 12 patients with a median follow-up of 7 months, with either PCN or PNET &amp;lt;2 cm. Eligible PCNs were either intraductal papillary mucinous neoplasms (IPMN) with worrisome features or mucinous cystic neoplasms (MCN) that were not eligible or refused surgery. Ablation was performed using a 19-gauge dedicated needle.

RESULTS

Twelve patients were treated, five had PCNs (four IPMNs, one MCN; median size of 36 mm, range 12-60) and seven had PNETs (median size 8.9 mm, range 6-18). Among patients with PCNs, the complete radiologic response was achieved in 3/5 (60%), partial response in 1/5 (20%) and failure in 1/5 (20%). Among six patients with nonfunctioning PNETs, the complete radiologic response was achieved in 4/6 (66.7%), partial radiologic response in 0/6 (0%) and failure in 2/6 (33.3%). Following a median follow-up of 7 months. One patient with insulinoma showed complete resolution of hypoglycemia-related symptoms. Three postprocedural adverse events occurred, including one case (1/12, 8.3%) of mild acute pancreatitis and two cases (2/12, 16.7%) of abdominal pain.

CONCLUSION

EUS-guided RFA for premalignant PCNs and PNETs is feasible and well-tolerated. Efficacy would be further evaluated with continued follow-up of patients.

Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) for advanced pancreatic and periampullary adenocarcinoma

Long term prognosis and 5-year survival for pancreatic adenocarcinoma (PDAC) remains suboptimal. Endoscopic ultrasound (EUS) guided RFA (EUS-RFA) is an emerging technology and limited data exist regarding safety and long-term outcomes. The aim of this study is to report safety-profile, feasibility and outcomes of EUS-RFA for advanced PDAC. Prospective review of patients with diagnosis of locally-advanced or metastatic PDAC undergoing EUS-RFA between October 2016 to March 2018 with long-term follow up (> 30 months). Study patients underwent a total of 1-4 RFA sessions. All patients were enrolled in longitudinal cohort study and received standard of care chemotherapy. 10 patients underwent EUS-RFA. Location of the lesions was in the head(4), neck(2), body(2), and tail(2). 22 RFA sessions were performed with a range of 1-4 sessions per patient. There were no major adverse events (bleeding, perforation, infection, pancreatitis) in immediate (up to 72 h) and short-term follow up (4 weeks). Mild worsening of existing abdominal pain was noted during post-procedure observation in 12/22 (55%) of RFA treatments. Follow-up imaging demonstrated tumor progression in 2 patients, whereas tumor regression was noted in 6 patients (> 50% reduction in size in 3 patients). Median survival for the cohort was 20.5 months (95% CI, 9.93-42.2 months). Currently, 2 patients remain alive at 61 and 81 months follow-up since initial diagnosis. One patient had 3 cm PDAC with encasement of the portal confluence, abutment of the celiac axis, common hepatic and superior mesenteric artery. This patient had significant reduction in tumor size and underwent standard pancreaticoduodenectomy. In our experience, EUS-RFA was safe, well-tolerated and could be concurrently performed with standard chemotherapy. In this select cohort, median survival was improved when compared to published survival based upon SEER database and clinical trials. Future prospective trials are needed to understand the role of EUS-RFA in overall management of PDAC.

The global research status and trends of the application of endoscopic ultrasonography in pancreatic tumors over the last decades: A bibliometric study

Background

To describe the development process and structural relationships of scientific achievements in endoscopic ultrasonography (EUS) in pancreatic tumors over the past decades and to reveal the key research topics using bibliometric analysis.

Methods

All relevant publications covering the research of EUS in pancreatic tumors from 1984 to 2021 were involved through the Web of Science Core Collection. R-bibliometrix was used to conduct the bibliometric analysis, and VOSviewer software was used to explore the hot spots and networks related to this field.

Results

Between 1984 and 2021, 4071 publications were involved. The number of annual publications increased from 1 to 310. The United States contributed the most publications to this field (n=1433, 35.20%), followed by Japan (n=827, 20.31%) and Germany (n=319, 7.84%). There was active cooperation between countries/regions. Gastrointestinal Endoscopy (GIE) was the most productive journal and the most influential journal. Professor Giovannini M, who produced the most publications, had a great influence on this research. The focus in this field was clarified by analyzing the top 10 citations and co-citations publications. Moreover, the analysis of the keywords showed Important topics: "Classification of pancreatic tumor disease" "Development of EUS in the diagnosis of pancreatic tumor diseases," and "Development of EUS in the treatment of pancreatic tumor diseases."

Conclusion

For the first time, bibliometric analysis was used to gain a deep understanding of the global trends of studies investigating EUS in pancreatic tumor diseases. The EUS field is rapidly evolving, and our study may be a critical reference for clinical researchers related to this field.

State of the Art in Endoscopic Therapy for the Management of Gastroenteropancreatic Neuroendocrine Tumors

OPINION STATEMENT

Gastroenteropancreatic neuroendocrine neoplasms (GEP NENs) comprise a heterogeneous group of slow growing tumors arising from the neuroendocrine cells of the gastrointestinal (GI) tract. Although they are considered relatively rare, their incidence is rising and it is believed that the more frequent use of endoscopy and imaging studies have at least in part contributed to the increased diagnosis especially of localized neoplasms. The management of these neoplasms should be guided by a multidisciplinary NEN team following appropriate staging investigations. Localized neoplasms of the GI tract may be suitable for endoscopic therapy, while patients with pancreatic NENs, unsuitable for surgery, should be considered for endoscopic ultrasound (EUS)-guided ablation. In this review, we discuss the evidence regarding endoscopic resection of luminal NENs and EUS-guided therapy of pancreatic NENs. The efficacy, safety, and other longer-term outcomes of these techniques are summarized. In conclusion, this review of endoscopic therapies for localized NENs may be a useful guide for NEN clinicians and endoscopists who are considering these therapeutic options for the management of focal GEP NENs.

EUS-RFA of the pancreas: where are we and future directions

Surgical resection remains the gold standard for pancreatic cancer, high-risk pancreatic neuroendocrine tumors (PNETs) and pancreatic cystic neoplasms (PCNs). However, a majority of pancreatic cancers are unresectable at the time of diagnosis. In addition, surgical resection of pancreatic lesions can be associated with morbidity and mortality. A less-invasive alternative therapeutic intervention to avoid short term and long-term adverse events is desirable, as is a minimally-invasive palliative therapy for unresectable or recurrent pancreatic cancers. Endoscopic ultrasound guided radiofrequency ablation (EUS-RFA) allows for selective tissue ablation with minimal injury to the surrounding tissue. EUS-RFA of pancreatic tumors has shown high clinical and technical success with acceptable side effects in pancreatic lesions, lymph nodes, and the celiac plexus. This paper will review the pathophysiology, available technology, safety and efficacy, and future directions of EUS-RFA.

EUS-guided radiofrequency and ethanol ablation for pancreatic neuroendocrine tumors: A systematic review and meta-analysis

EUS-guided radiofrequency ablation (RFA) and ethanol ablation (EA) for pancreatic neuroendocrine tumors (PNETs) have recently been reported with good outcomes. We performed a systematic review and meta-analysis to evaluate the comparative effectiveness and safety of EUS-RFA and EUS-EA in the treatment of PNETs. A comprehensive search of multiple databases (through October 2020) was performed to identify studies that reported outcomes of EUS-RFA and EUS-EA of PNETs. Outcomes assessed included clinical success, technical success, and adverse events (AEs). A total of 181 (100 EUS-RFA, 81 EUS-EA) patients (60.7 ± 9.2 years) with 204 (113 EUS-RFA, 91 EUS-EA) PNETs (mean size 15.1 ± 4.7 mm) were included from 20 studies. There was no significant difference in the rates of technical success (94.4% [95% confidence interval (CI): 88.5–97.3, I² = 0] vs. 96.7% [95% CI: 90.8–98.8, I² = 0]; P = 0.42), clinical success (85.2% (95% CI: 75.9–91.4, I² = 0) vs. 82.2% [95% CI: 68.2–90.8, I² = 10.1]; P = 0.65), and AEs (14.1% [95% CI: 7.1–26.3, I² = 0] vs. 11.5% [95% CI: 4.7–25.4, I² = 63.5]; P = 0.7) between EUS-RFA and EUS-EA, respectively. The most common AE was pancreatitis with the rate of 7.8% and 7.6% (P = 0.95) for EUS-RFA and EUS-EA, respectively. On meta-regression, the location of PNETs in head/neck of pancreas (P = 0.03) was a positive predictor of clinical success for EUS-RFA. EUS-RFA and EUS-EA have similar effectiveness and safety for PNETs ablation. Head/neck location of PNETs was a positive predictor for clinical success after EUS-RFA.

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.

Endoscopic ultrasound-guided ethanol and radiofrequency ablation of pancreatic insulinomas: a systematic literature review

BACKGROUND

Insulinoma is the most common neuroendocrine neoplasm of the pancreas, characterised by hypoglycaemic symptoms. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) and ethanol ablation (EUS-EA) are novel methods for treating insulinoma.We aimed to perform a systematic review to assess the efficacy and safety of EUS-guided ablation techniques for pancreatic insulinomas.

METHODS

We systematically searched for articles detailing EUS-guided ablations of insulinomas. We performed a qualitative analysis and summarised data on the efficacy and safety of EUS-RFA and EUS-EA techniques.

RESULTS

In total, we identified 35 case reports and case series describing 75 patients with insulinomas treatment with EUS-guided ablation. Twenty-seven patients were treated with EUS-RFA, 47 patients with EUS-EA, and 1 patient received EUS-EA and EUS-RFA in the same session. In total, 84 insulinomas were ablated (EUS-RFA: 31, EUS-EA: 53). Most insulinomas were in the head of the pancreas (40%). The clinical success rate for EUS-guided ablation techniques was 98.5%. The median glucose level was 1.95 (Q1-Q3: 1.69-2.13) mmol/L before ablation compared to 6.20 (Q1-Q3: 5.30-7.05) mmol/L after treatment. The median insulin and C-peptide levels before and after RFA/EA were 230 (Q1-Q2: 120-257) pmol/L and 41 (Q1-Q2 35-42) pmol/L; 2077 (Q1-Q2 1644-2459) pmol/L and 819 (Q1-Q2 696-1072) pmol/L, respectively. There were eleven adverse events: seven abdominal pain, two mild acute pancreatitis, one necrotising acute pancreatitis and one local hematoma. All patients recovered, and there were no periprocedural deaths.

CONCLUSIONS

EUS-guided ablation of insulinoma seems to be a safe and effective treatment and is an alternative to surgical resection in selected cases.

[Large Animal Models in Pancreas and Biliary Disease]

Rodent models, which have played important roles in preclinical research of pancreas and biliary diseases, have some limitations to translating data from rodent models to human diseases. Large animal models have recently been developed to overcome these limitations and perform translational research of medical devices and drugs in pancreas and biliary diseases. Preclinical studies using large animal models are necessary before clinical application, especially for the research and development of equipment, instrumentation, and techniques in pancreato-biliary diseases. As long as the endoscope used in humans can enter an organ, there appears to be no limitation in terms of species or organ for endoscopic experiments of large animal models. Investigators have mainly used swine for pancreas and biliary endoscopic experiments. Until now, unique swine models that investigators have been established include the normal bile duct model, bile duct dilation model, bile duct dilation+direct peroral cholangioscopy model, benign biliary stricture model, hilar biliary obstruction model, and acute pancreatitis (post-ERCP pancreatitis) model. Many preclinical studies have been performed using these established endoscopy-based large animal models to develop novel medical devices. Furthermore, porcine pancreatic cancer models induced by a transgenic or orthotopic method are currently under development. These models appear to be available for general use in the future and will have multiple potential preclinical and clinical applications.

Personalized Approach to the Role of Endoscopic Ultrasound in the Diagnosis and Management of Pancreaticobiliary Malignancies

Pancreaticobiliary malignancies arise from different areas within the pancreas and biliary tree. Endoscopic ultrasound (EUS) is a well-recognized diagnostic and therapeutic modality in the treatment of pancreaticobiliary diseases, and more specifically, pancreaticobiliary malignancies. Traditionally used for diagnostic purposes, EUS plays a critical role in tissue sampling and cancer staging. The emergence of the new field of interventional EUS has allowed EUS to also play a critical role in therapeutic management. Novel interventional EUS procedures such as EUS-guided gastrojejunostomy (EUS-GE), EUS-guided biliary drainage (EUS-BD), and EUS-guided gallbladder drainage (EUS-GLB) can be utilized to treat complications of pancreaticobiliary malignancies such as gastric outlet obstruction, obstructive jaundice, and cholecystitis. In addition, interventional EUS procedures can be utilized for the palliation of unresectable malignancies both for source control with EUS-radiofrequency ablation (EUS-RFA) and for the treatment of abdominal pain refractory to opioid medications with EUS-guided celiac axis neurolysis. However, patient selection remains a critical component in both diagnostic and therapeutic interventions and must be tailored to individual patient wishes, disease pathology, and overall prognosis.

Role of Radiofrequency Ablation in the Management of Unresectable Pancreatic Cancer

Pancreatic cancer is one of the most aggressive malignancies of the digestive tract and carries a poor prognosis. The majority of patients have advanced disease at the time of diagnosis. Surgical resection offers the only curative treatment, but only a small proportion of patients can undergo surgical resection. Radiofrequency ablation (RFA) is a well-known modality in the management of solid organ tumors, however, its utility in the management of pancreatic cancer is under investigation. Since the past decade, there is increasing use of RFA as it provides a feasible palliation treatment in the management of unresectable pancreatic cancer. RFA causes tumor cytoreduction through multiple mechanisms such as coagulative necrosis, protein denaturation, and activation of anticancer immunity. The safety profile of RFA is controversial because of the high risk for complications, however, small prospective and retrospective studies have shown promising results in its applicability for palliative management of unresectable pancreatic malignancies. In this review, we discuss different approaches of RFA, their indications, technical accessibility, safety, and major complications in the management of unresectable pancreatic cancer.

Endoscopic ultrasound-guided ethanol ablation for the management of a symptomatic pancreatic insulinoma

INTRODUCTION

pancreatic insulinoma is a sporadic, usually benign, frequently solitary tumor that is smaller than 20 mm. When it is functioning, patients present with symptoms of hypoglycemia secondary to insulin hypersecretion. The diagnosis is clinical, with biochemical and radiological confirmation. Surgery is the management of choice, although endoscopic ultrasound-guided ablation is currently being developed.

MATERIAL AND METHODS

we present a prospective case series of pancreatic insulinoma patients with symptoms of severe hypoglycemia, who were treated with endoscopic ultrasound-guided ethanol ablation as an alternative to surgical management.

RESULTS

technical and clinical success was achieved in all cases and there were no complications associated with the procedure.

CONCLUSION

the treatment of symptomatic insulinoma by endoscopic ultrasound-guided ethanol ablation could be a safe and effective alternative to surgical management in non-surgical patients or those who refuse surgery.

Endoscopic Ultrasound-Guided Local Therapy for Pancreatic Neoplasms

Surgical resection is considered the only treatment option for pancreatic cancer and other pancreatic neoplasms with malignant potential, such as neuroendocrine tumors, mucinous cystic neoplasms, and intraductal papillary mucinous neoplasms. However, only 10%-20% of all patients with pancreatic cancer present with resectable forms of the disease as the symptoms are rarely manifested during the early stages, and the disease tends to progress rapidly. Furthermore, pancreatic surgery is associated with high rates of morbidity and mortality. The development of linear-array endoscopic ultrasound (EUS) techniques has increased the indications of EUS-guided local therapy for pancreatic neoplasms. We assessed the studies that investigated various treatment modalities, such as fine-needle injection, radiofrequency ablation, irreversible electroporation, and radiotherapy, under EUS guidance to better understand the usefulness of these techniques with respect to the efficacy and associated complications.

Advances in Interventional Endoscopic Ultrasound (EUS): A Technical Review

Endoscopic ultrasound (EUS) has become the therapeutic intervention of choice for multiple diseases and continues to evolve rapidly. Its increasing use has allowed the development and adaptation of multiple, revolutionary devices and tools. Currently, there is paucity of randomized clinical trials evaluating multiple EUS-guided interventions and the vast majority of published data is heterogenous. However, the available literature on EUS-guided therapeutic interventions continues to expand and demonstrate its safety, efficacy and cost effectiveness in carefully selected patients when performed by expert endosonographers. The future of interventional EUS appears to be bright!

Endosonography-guided Radiofrequency Ablation in Pancreatic Diseases: Time to Fill the Gap Between Evidence and Enthusiasm

Over the past 20 years, endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) has generated interest as a novel minimally invasive tool in the multimodal treatment of pancreatic malignant and premalignant lesions. However, although optimization of probes and settings has made EUS-RFA relatively safe, questions on the ideal positioning of this treatment in a multimodal strategy remain unanswered. This review will summarize the technical aspects of EUS-RFA and available clinical experiences for each pancreatic indication (pancreatic cancer, neuroendocrine neoplasms, cystic lesions, and celiac ganglia neurolysis). Established indications will be discussed along those requiring additional clinical data or even proof-of-concept studies. A dedicated session will further discuss evidence expected to emerge from ongoing registered trials, together with issues that must be addressed in future research, including the possible combination with immunotherapy, and the personalization of this treatment on the basis of genetic profiling. Despite the great clinical enthusiasm and scientific fervor, while evidence-based answers are produced, EUS-RFA must be centralized in high-volume centers of recognized expertise, where multidisciplinary discussions of indications and actively recruiting research protocols are available.

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.

Endoscopic ultrasound in pancreatic cancer treatment: Facts and hopes

Pancreatic ductal adenocarcinoma is one of the most common causes of cancer-related deaths. Since most patients present with advanced disease, its prognosis is dismal. New and more effective therapeutic strategies are needed. Endoscopic ultrasound is currently an indispensable tool for the diagnosis and staging of pancreatic ductal adenocarcinoma. In recent years, endoscopic ultrasound has evolved to become also a therapeutic procedure. On one hand, the role of endoscopic ultrasound in the management of pancreatic cancer-related symptoms (pain, obstructive jaundice, and gastric outlet obstruction) is now well established. On the other hand, its use as a mean to the delivery of anti-tumor therapies (injecting anti-tumor agents, assisting in radiotherapy, and guiding ablative therapies) is still mostly experimental, despite growing evidence supporting its feasibility, safety and efficacy.

Endoscopic Ultrasound-Guided Radiofrequency Ablation: A New Therapeutic Approach for Pancreatic Neuroendocrine Tumors

CONTEXT

Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is rapidly emerging as feasible therapy for patients with pancreatic neuroendocrine tumors (pNETs) in selected cases, as a result of its favorable safety profile.

OBJECTIVE

To assess the feasibility, safety, and efficacy of EUS-RFA in a cohort of patients with functional and nonfunctional pNETs (NF-pNETs).

DESIGN

Data on pNET patients treated with EUS-RFA between March 2017 and October 2018 at two tertiary centers was retrospectively analyzed.

RESULTS

The cohort included 18 adults (eight women, 10 men), aged 60.4 ± 14.4 years (mean ± SD), seven insulinoma patients, and 11 patients with NF-pNETs. Twenty-seven lesions with a mean diameter of 14.3 ± 7.3 mm (range 4.5 to 30) were treated. Technical success defined as typical postablative changes on a surveillance imaging was achieved in 26 out of 27 lesions. Clinical response with normalization of glucose levels was observed in all (seven of seven) insulinoma cases within 24 hours of treatment. Overall, there were no major complications 48 hours postprocedure. No clinically significant recurrences were observed during mean follow-up of 8.7 ± 4.6 months (range 2 to 21 months).

CONCLUSIONS

EUS-guided RFA of pNETs is a minimally invasive, safe, and technically feasible procedure for selected patients.

Endoscopic Palliation for Biliary and Pancreatic Malignancies: Recent Advances

Malignancies of the pancreatobiliary system are usually unresectable at the time of diagnosis. As a consequence, a majority of these cases are candidates for palliative care. With advances in chemotherapeutic agents and multidisciplinary care, the survival rate in pancreatobiliary malignancies has improved. Therefore, there is a need to provide an effective and long-lasting palliative care for these patients. Endoscopic palliation is preferred to surgery as the former is associated with equal efficacy and reduced morbidity. The main role of endoscopic palliation in the vast majority of pancreatobiliary malignancies includes biliary and enteral stenting for malignant obstructive jaundice and gastric outlet obstruction, respectively. Recent advances in endoscopic palliation appear promising in imparting long-lasting relief of symptoms. Use of radiofrequency ablation and photodynamic therapy in malignant biliary obstruction has been shown to improve the survival rates as well as the patency of biliary stents. The emergence of endoscopic ultrasound (EUS) as a therapeutic tool has enhanced the capability of minimally invasive palliation in pancreatobiliary cancers. EUS is a valuable alternative to endoscopic retrograde cholangiopancreatography for the palliation of obstructive jaundice. More recently, EUS is emerging as an effective primary modality for biliary and gastric bypass.

EUS-guided pancreatic radiofrequency ablation: preclinical comparison of two currently available devices in a pig model

Introduction  Two devices are currently available to perform pancreatic radiofrequency ablation (P-RFA). Potential clinical indications might extend from the treatment of pancreatic cystic lesions to ablation of small pancreatic solid lesions or cytoreduction of advanced pancreatic adenocarcinomas, but more preclinical data from animal models are needed to optimize P-RFA operation. Methods  P-RFA was performed under laparotomy and under endoscopic ultrasonographic guidance on the liver and pancreatic parenchyma of four live swine using the Habib EUS RFA (EMcision Ltd, London, UK) probe and the EUS-RA needle (Taewoong Medical, Gyeonggi-do, South Korea). Animals were sacrificed 2 hours after the procedure. Influence of tuning ablation time and power on tissue ablation were studied by histopathological assessment of the maximal depth of tissue damage on representative slides for each P-RFA shot. Results  The Habib probe in the liver parenchyma resulted in tissue necrosis increasing within the range of 1.9 ± 0.5 mm (Power = 8 W, Time = 120 s) to 2.5 ± 1 mm (Power = 10 W, Time = 120 s). In the pancreatic parenchyma, tissue damage ranged from 3.1 ± 0.4 mm (Power = 8 W, Time = 120 s) to 2.3 ± 0.1 mm (12 W, 120 s) in depth. EUS RFA ablation of the liver parenchyma resulted in tissue damage ranging from 1.6 ± 0.2 mm (Power = 30 W, Time = 11 s) to 1.5 ± 0.1 mm (Power = 70 W, Time = 9 s); in the pancreas, ablation depth ranged from 3.6 ± 0.5 mm (Power = 30 W, Time = 15 s) to 3.8 ± 0.4 mm (Power = 70 W, Time = 11 s). Conclusion  Both devices allow for effective ablation of pancreatic tissue within 1.5 to 3.8 mm around the RFA electrode, with a modest influence of tuning power settings. Specific settings are recommended for each of the devices studied. Ablation of larger lesions may require more repeat P-RFA shots in different locations rather than a simple modulation of ablation parameters.

Thermal ablation of pancreatic cancer: A systematic literature review of clinical practice and pre-clinical studies

PURPOSE

Pancreatic cancer is a challenging malignancy with low treatment option and poor life expectancy. Thermal ablation techniques were proposed as alternative treatment options, especially in advanced stages and for unfit-for-surgery patients. This systematic review describes the thermal ablative techniques -i.e., Laser (LA), Radiofrequency (RFA), Microwave (MWA) Ablation, High-Intensity Focused Ultrasound (HIFU) and cryoablation- available for pancreatic cancer treatment. Additionally, an analysis of the efficacy, complication rate and overall survival for each technique is conducted.

MATERIAL AND METHODS

This review collects the ex vivo, preclinical and clinical studies presenting the use of thermal techniques in the pancreatic cancer treatment, searched up to March 2018 in PubMed and Medline. Abstracts, letters-to-the-editor, expert opinions, reviews and non-English language manuscripts were excluded.

RESULTS

Sixty-five papers were included. For the ex vivo and preclinical studies, there are: 12 records for LA, 8 for RFA, 0 for MWA, 6 for HIFU, 1 for cryoablation and 3 for hybrid techniques. For clinical studies, 1 paper for LA, 14 for RFA, 1 for MWA, 17 for HIFU, 1 for cryoablation and 1 for hybrid techniques.

CONCLUSIONS

Important technological advances are presented in ex vivo and preclinical studies, as the real-time thermometry, nanotechnology and hybrid techniques to enhance the thermal outcome. Conversely, a lack of standardization in the clinical employment of the procedures emerged, leading to contrasting results on the safety and feasibility of some analyzed techniques. Uniform conclusions on the safety and feasibility of these techniques for pancreatic cancer will require further structured investigation.

Endoscopic ultrasound-guided radiofrequency ablation for management of benign solid pancreatic tumors

BACKGROUND

Radiofrequency ablation (RFA) has been increasingly employed in experimental and clinical settings for the management of pancreatic lesions. This study aimed to assess the safety and efficacy of endoscopic ultrasound (EUS)-guided RFA for benign solid pancreatic tumors.

METHODS

In a single-center, prospective study, 10 patients with benign solid pancreatic tumors underwent EUS-RFA. After the RFA electrode had been inserted into the pancreatic mass, the radiofrequency generator was activated to deliver 50 W of ablation power.

RESULTS

Among the 10 patients, 16 sessions of EUS-RFA were successfully performed. Diagnoses included nonfunctioning neuroendocrine tumor (n = 7), solid pseudopapillary neoplasm (n = 2), and insulinoma (n = 1); the median largest diameter of the tumors was 20 mm (range 8 - 28 mm). During follow-up (median 13 months), radiologic complete response was achieved in seven patients. Two adverse events (12.4 %; 1 moderate and 1 mild) occurred.

CONCLUSIONS

EUS-RFA may be a safe and potentially effective treatment option in selected patients with benign solid pancreatic tumors. Multiple sessions may be required if there is a remnant tumor, and adverse events must be carefully monitored.

EUS-guided irreversible electroporation using endoscopic needle-electrode in porcine pancreas

BACKGROUND

Endoscopic irreversible electroporation (IRE) can be performed using a flexible, thin, needle-shaped electrode for an endoscopic ultrasound (EUS)-guided procedure. This study aimed to evaluate the feasibility and efficacy of performing EUS-guided IRE with endoscopic needle-electrode in porcine pancreas.

METHODS

Experimental endoscopic IRE on the pancreas were performed by EUS-guided approach in three pigs and compared with surgical approach in three pigs. The animals were killed after 24 h and their pancreases collected.

RESULTS

IRE ablation using endoscopic needle-electrode was successful technically in EUS-guided approaches for the pancreas. Immediately following IRE, the ablated pancreatic tissue showed no gross change except focal hemorrhage. H&E staining presented a well-demarcated ablation site measuring 1.0-1.5 cm in diameter in the pancreas. TUNEL immunohistochemistry showed diffuse cell death along the puncture site 24 h after IRE. No complication was observed in pigs after endoscopic IRE ablation.

CONCLUSION

EUS-guided IRE ablation was feasible and effective for pancreas using the newly developed device.