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

Efficacy and safety of endoscopic ultrasonography-guided radiofrequency ablation of small pancreatic neuroendocrine neoplasms: A prospective, pilot study

Objectives

Endoscopic ultrasonography (EUS)-guided radiofrequency ablation has recently been introduced as one of the management strategies for small pancreatic neuroendocrine neoplasms (PNENs). However, prospective data on its safety and efficacy remain limited.

Methods

This prospective pilot study was conducted at Okayama University Hospital from May 2023 to December 2024. Patients with grade 1 PNENs ≤15 mm, confirmed by EUS-guided fine-needle aspiration, were included. The primary endpoint was safety (adverse events [AEs] evaluated according to the 2010 guidelines of the American Society for Gastrointestinal Endoscopy. Severe AEs were defined as moderate or higher in American Society for Gastrointestinal Endoscopy grading and grade ≥3. Secondary endpoints included efficacy (complete response on contrast-enhanced computed tomography at 1 and 6 months), treatment details, device failure, diabetes mellitus exacerbation, and overall survival at 6 months.

Results

Five patients with non-functional PNENs (median age: 64 years; median tumor size: 10 mm) were treated. AEs occurred in two patients (40%, 2/5), although none was severe. Both patients developed asymptomatic pseudocysts, one experienced mild pancreatitis, and both resolved with conservative treatment. The complete response rates on contrast-enhanced computed tomography at one and 6 months were 100%. The median procedure time was 16 min without any device failure, and the median hospitalization was 5 days. None of the patients developed new-onset or worsening diabetes mellitus. The 6-month overall survival rate was 100%.

Conclusion

EUS-guided radiofrequency ablation demonstrated a high complete response rate with no severe AEs in this pilot study, suggesting a minimally invasive option for small, low-grade PNENs (jRCTs062230014).

Role of Endoscopy in Clinical Management of Intraductal Papillary Mucinous Neoplasms

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a well-recognized precursor of pancreatic carcinoma. Along with cross-sectional abdominal imaging tests, endoscopic examinations remain the cornerstone in the diagnosis of pancreatic cysts, early detection of IPMN-derived carcinomas, and risk stratification of patients with IPMNs for subsequent surveillance strategies. In particular, endoscopic ultrasound (EUS) facilitates the optimal patient management by providing high-resolution morphological information, and the contrast-enhanced harmonic mode may further enhance diagnostic accuracy. EUS-guided fine-needle aspiration for solid mass and/or cyst fluid is considered for pathological and molecular examinations for the diagnosis of pancreatic cysts and malignancy. Emerging evidence suggests the usefulness of through-the-needle biopsy and confocal laser microendoscopy in this setting. In addition to the undoubtful diagnostic utility, recent studies have demonstrated the potential effect of endoscopic interventions (i.e., ablation) on the control of IPMNs. Despite the increasing role of endoscopy in the clinical management of IPMNs, there remains a gap in our understanding of how to utilize endoscopy in the personalized care for patients with IPMNs (e.g., the optimal interval of EUS) and the prevention of deaths due to pancreatic carcinomas developing concomitantly with IPMNs. This review summarizes the current evidence on the role of endoscopy in both the diagnostic and therapeutic landscapes of clinical management of IPMNs and identifies key clinical unmet needs that should be addressed in future research. Combined with emerging technologies (e.g., artificial intelligence and high-throughput molecular profiling), endoscopy would offer more effective and tailored management strategies for patients with IPMNs.

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.

Mural nodules and prevalence of high-grade dysplasia in branch duct intraductal papillary mucinous neoplasm of the pancreas undergoing resection

BACKGROUND

A mural module (MN) within a branch-duct intraductal papillary mucinous neoplasm (BD-IPMN) could be a potential target for local treatment. The main aim was to describe the location of the highest grade of dysplasia relative to the mural module to assess the relevance of local treatment.

METHODS

Observational study of patients who underwent a pancreatic resection for suspected high-risk IPMN because of a mural module within a BD-IPMN (2012-2022). All patients had preoperative imaging confirming the enhancing mural module. The mural module was considered as a theoretical appropriate target for local destruction if no cancer or high-grade dysplasia (HGD) was described elsewhere than in the mural module.

RESULTS

Eighty-two patients (male: 44 (54%); mean age: 65 ± 9.2 years) were included. The mean size of BD-IPMN containing the mural module was 32 ± 14.8 mm. The mural module mean diameter was 10.5 ± 5.6 mm, and the main pancreatic duct (MPD) mean diameter was 5.2 ± 3.6 mm. Six patients presented invasive carcinoma (7%), 37 had HGD (45%), and 39 (48%) had exclusively low-grade dysplasia. The mural module was dysplastic in 70 cases (85%). The mural module was considered a relevant target for local ablation in 45 patients (55%), whereas 37 patients (45%) had HGD/invasive carcinoma distant from the mural module. HGD was exclusively present in the mural module in 6/82 patients (7%). Factors independently associated with 'relevant indication for local treatment' were female gender (P = 0.004; OR = 5.2, 95% c.i. 1.7 to 15.9) and MPD < 5 mm (P < 0.0001; OR = 8.6, 95% c.i. 2.7 to 26.8).

CONCLUSION

In resected pancreata, BD-IPMN mural modules are associated with HGD distant from the mural module almost half of cases. The findings question the safety of local treatment, supporting pancreatectomy as the best approach.

Percutaneous Ultrasound-Guided Radiofrequency Ablation as a Therapeutic Approach for the Management of Insulinomas and Associated Metastases in Dogs

Insulinomas are the most common neoplasms of the endocrine pancreas in dogs, leading to persistent hypoglycemia due to inappropriate insulin secretion. The standard treatment is surgical resection, but it carries significant risks, including pancreatitis and diabetes mellitus. This study investigates the efficacy and safety of percutaneous ultrasound-guided radiofrequency ablation (RFA) as an alternative to surgery. A total of 29 dogs diagnosed with insulinoma were treated with RFA, targeting both primary pancreatic tumors and metastases in regional lymph nodes or the liver. Blood glucose levels and tumor size were monitored before and after the procedure. RFA led to a significant increase in blood glucose levels and a reduction in tumor size in all patients, with minimal postoperative complications. The results suggest that RFA is a feasible and effective treatment option for insulinomas in dogs.

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 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.

Endoscopic ultrasound-guided radiofrequency ablation of pancreatic tumors

PURPOSE OF REVIEW

Surgery is a cornerstone in the management of pancreatic cancer and precancerous pancreatic lesions. However, many patients are not suitable candidates for surgery at the time of diagnosis for various reasons. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) appears to be a promising treatment option for patients who are ineligible for surgery for management of pancreatic adenocarcinoma (PDAC), and pancreatic neuroendocrine tumors (PNETs), and pancreatic cystic lesions (PCLs).

RECENT FINDINGS

EUS-RFA may serve as an adjunct to chemotherapy or palliative measures for inoperable cases of PDAC. Given its feasibility and efficacy, EUS-RFA has an evolving niche as a minimally invasive and potentially definitive treatment for PNETs and high-risk PCLs such as intraductal papillary mucinous neoplasms (IPMNs). EUS-RFA is a generally well tolerated procedure, with abdominal pain and acute pancreatitis being the most common adverse effects, though the risk can be mitigated through prophylactic measures.

SUMMARY

There is an increasing body of evidence to support the use of EUS-RFA in managing pancreatic lesions, either as definitive, adjunctive, or palliative treatment, depending on lesion type.

Portuguese Pancreatic Club Perspectives on Endoscopic Ultrasound-Guided and Surgical Treatment of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (panNETs) are a group of neoplasms with heterogenous biological and clinical phenotypes. Although historically regarded as rare, the incidence of these tumors has been increasing, mostly owing to improvements in the detection of small, asymptomatic tumors with imaging. The heterogeneity of these lesions creates significant challenges regarding diagnosis, staging, and treatment. Endoscopic ultrasound (EUS) has improved the characterization of pancreatic lesions. Furthermore, EUS nowadays has evolved from a purely diagnostic modality to allow the performance of minimally invasive locoregional therapy for pancreatic focal lesions. The choice of treatment as well as the treatment goals depend on several factors, including tumor secretory status, grading, staging, and patient performance status. Surgery has been the mainstay for the management of these patients, particularly for localized, low-grade, large panNETs >2 cm. Over the last decade, a significant body of evidence has been accumulated evaluating the role of EUS for the ablative therapy of panNETs, namely by the use of chemoablative agents and radiofrequency. Although endoscopic techniques are not routinely recommended by international guidelines, they may be considered for the treatment of smaller lesions in patients who are unwilling or unfit for pancreatic surgery. In this review, we summarize the existing evidence on the interventional techniques for the treatment of patients with panNETs, focusing on the EUS-guided and surgical approaches.

Endoscopic Ultrasound-Guided Ablation of Pancreatic Mucinous Cysts

Endoscopic ultrasound (EUS) has rapidly evolved from a diagnostic to a therapeutic tool with applications for various pancreaticobiliary diseases. As part of this evolution, EUS-guided chemoablation for neoplastic pancreatic cysts is developing as a minimally invasive treatment option for appropriately selected mucinous cysts, which can spare patients major resective surgery and may reduce progression to pancreatic cancer. Chemotherapeutic cyst ablation has demonstrated encouraging complete resolution rates, while an alcohol-free chemoablation protocol has demonstrated a significant decrease in adverse events without a compromise to complete ablation rates when compared with previous alcohol-based protocols. Most pancreatic cysts are small, low risk, and best managed by surveillance per accepted guidelines. Cysts with features suggestive of overt malignancy are best discussed by a multidisciplinary committee, and surgery is considered if appropriate. However, for patients in the middle ground with cysts that are structurally suitable for chemoablation, alcohol-free chemoablation has been shown to allow effective, safe, and durable results especially for those who are not ideal operative candidates. EUS-guided alcohol-free chemoablation is promising and continues to evolve; however, as a relatively novel treatment option it has areas of uncertainty that will require further investigation and development.

Safety and efficacy of endoscopic ultrasound-guided radiofrequency ablation for pancreatic neuroendocrine neoplasms: Systematic review and meta-analysis

OBJECTIVE

Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) has been constantly increasing, particularly in the treatment of pancreatic neuroendocrine neoplasms (pNENs). While emerging data in this field are accumulating, we aimed to assess the pooled efficacy and safety of EUS-RFA for pNENs.

METHODS

The PubMed/Medline, Embase, and Cochrane Library databases search was conducted to identify studies reporting EUS-RFA of pNENs with outcomes of interest (efficacy and safety). The primary outcome was radiological response. Efficacy was assessed by the pooled clinical response rate, whereas safety was assessed by the pooled adverse events (AEs) rate. Heterogeneity was assessed using I2. Pooled estimates and the 95% confidence interval (CI) were calculated using a random-effect model.

RESULTS

Eleven studies involving 292 patients were included. The pooled technical success rate was 99.2% (95% CI 97.9-99.9%), with no heterogeneity. The pooled complete radiological response was 87.1% (95% CI 80.1-92.8%). The pooled partial response was 11.4% (95% CI 6.2-18.1%). The pooled clinical response rate for functional pNENs was 94.9% (95% CI 90.7-97.9%), with no heterogeneity. The pooled incidence of AEs was 20.0% (95% CI 14.0-26.7%); most AEs were mild to moderate in grade, while the pooled incidence of severe AEs was 0.9% (95% CI 0.2-2.3%). The most common AEs were transient mild abdominal pain in 19 patients (6.5%), and mild to moderate pancreatitis in 23 patients (7.9%). No cases of mortality were reported.

CONCLUSION

Endoscopic ultrasound-guided radiofrequency ablation resulted on a feasible approach for pNENs treatment, with excellent technical success, high radiological and clinical response, and acceptable AE rate.

Endoscopic Ultrasound-Guided Ablation of Premalignant Pancreatic Cysts and Pancreatic Cancer

Pancreatic cancer is on the rise and expected to become the second leading cause of cancer-related death by 2030. Up to a one-fifth of pancreatic cancers may arise from mucinous pancreatic cysts, which are frequently present in the general population. Currently, surgical resection is the only curative approach for pancreatic cancer and its cystic precursors. However, only a dismal proportion of patients are eligible for surgery. Therefore, novel treatment approaches to treat pancreatic cancer and precancerous pancreatic cysts are needed. Endoscopic ultrasound (EUS)-guided ablation is an emerging minimally invasive method to treat pancreatic cancer and premalignant pancreatic cysts. Different ablative modalities have been used including alcohol, chemotherapy agents, and radiofrequency ablation. Cumulative data over the past two decades have shown that endoscopic ablation of mucinous pancreatic cysts can lead to cyst resolution in a significant proportion of the treated cysts. Furthermore, novel data are emerging about the ability to endoscopically ablate early and locally advanced pancreatic cancer. In this review, we aim to summarize the available data on the efficacy and safety of the different EUS-ablation modalities for the management of premalignant pancreatic cysts and pancreatic cancer.

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.

Endoscopic Ultrasound-Guided Locoregional Treatments for Solid Pancreatic Neoplasms

Solid pancreatic neoplasms are one of the most diagnosed gastrointestinal malignancies thanks to the current and progressive advances in radiologic methods. Endoscopic ultrasound-guided techniques have over time gained a prominent role in the differential diagnosis and characterization of these pancreatic lesions, including pancreatic cancer, neuroendocrine tumors, and metastases. Recently, several endoscopic ultrasound-guided locoregional treatment techniques, which are divided into thermal ablative techniques and non-thermal injection techniques, have been developed and applied in different settings for the treatment of solid pancreatic neoplasms. The most common ablative techniques are radiofrequency, microwave, laser, photodynamic therapy and hybrid techniques such as hybrid cryothermal ablation. The most common injection techniques are ethanol injection, immunotherapy and brachytherapy. In this review, we update evidence about the efficacy and safety of endoscopic ultrasound-guided locoregional treatments for solid pancreatic neoplasms.

An Overview of Pancreatic Neuroendocrine Tumors and an Update on Endoscopic Techniques for Their Management

The growing importance of advanced endoscopy in the diagnosis and treatment of pancreatic neuroendocrine neoplasms (PanNETs) necessitates a comprehensive understanding of various biochemical markers, genetic testing methods, radiological techniques, and treatment approaches that encompass multiple disciplines within and beyond gastrointestinal oncology. This review aims to highlight key aspects of these topics, with a specific focus on emerging EUS-guided procedures for the management of PanNETs.

Endoscopic Ultrasound-Guided Local Ablative Therapies for the Treatment of Pancreatic Neuroendocrine Tumors and Cystic Lesions: A Review of the Current Literature

Since its emergence as a diagnostic modality in the 1980s, endoscopic ultrasound (EUS) has provided the clinician profound access to gastrointestinal organs to aid in the direct visualization, sampling, and subsequent identification of pancreatic pathology. In recent years, advancements in EUS as an interventional technique have promoted the use of local ablative therapies as a minimally invasive alternative to the surgical management of pancreatic neuroendocrine tumors (pNETs) and pancreatic cystic neoplasms (PCNs), especially for those deemed to be poor operative candidates. EUS-guided local therapies have demonstrated promising efficacy in addressing a spectrum of pancreatic neoplasms, while also balancing local adverse effects on healthy parenchyma. This article serves as a review of the current literature detailing the mechanisms, outcomes, complications, and limitations of EUS-guided local ablative therapies such as chemical ablation and radiofrequency ablation (RFA) for the treatment of pNETs and PCNs, as well as a discussion of future applications of EUS-guided techniques to address a broader scope of pancreatic pathology.

Performance and Safety of EUS Ablation Techniques for Pancreatic Cystic Lesions: A Systematic Review and Meta-Analysis

BACKGROUND

Pancreatic cystic lesions (PCL) represent an increasingly diagnosed condition with significant burden to patients' lives and medical resources. Endoscopic ultrasound (EUS) ablation techniques have been utilized to treat focal pancreatic lesions. This systematic review with meta-analysis aims to assess the efficacy of EUS ablation on PCL in terms of complete or partial response and safety.

METHODS

A systematic search in Medline, Cochrane and Scopus databases was performed in April 2023 for studies assessing the performance of the various EUS ablation techniques. The primary outcome was complete cyst resolution, defined as cyst disappearance in follow-up imaging. Secondary outcomes included partial resolution (reduction in PCL size), and adverse events rate. A subgroup analysis was planned to evaluate the impact of the available ablation techniques (ethanol, ethanol/paclitaxel, radiofrequency ablation (RFA), and lauromacrogol) on the results. Meta-analyses using a random effects model were conducted and the results were reported as percentages with 95% confidence intervals (95%CI).

RESULTS

Fifteen studies (840 patients) were eligible for analysis. Complete cyst resolution after EUS ablation was achieved in 44% of cases (95%CI: 31-57; 352/767; I² = 93.7%), and the respective partial response rate was 30% (95%CI: 20-39; 206/767; I² = 86.1%). Adverse events were recorded in 14% (95%CI: 8-20; 164/840; I² = 87.2%) of cases, rated as mild in 10% (95%CI: 5-15; 128/840; I² = 86.7%), and severe in 4% (95%CI: 3-5; 36/840; I² = 0%). The subgroup analysis for the primary outcome revealed rates of 70% (95%CI: 64-76; I² = 42.3%) for ethanol/paclitaxel, 44% (95%CI: 33-54; I²= 0%) for lauromacrogol, 32% (95%CI: 27-36; I² = 88.4%) for ethanol, and 13% (95%CI: 4-22; I² = 95.8%) for RFA. Considering adverse events, the ethanol-based subgroup rated the highest percentage (16%; 95%CI: 13-20; I² = 91.0%).

CONCLUSION

EUS ablation of pancreatic cysts provides acceptable rates of complete resolution and a low incidence of severe adverse events, with chemoablative agents yielding higher performance rates.

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.

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.

Management of Small Nonfunctioning Pancreatic Neuroendocrine Neoplasms: Current Opinion and Controversies

The incidence of small and asymptomatic pancreatic neuroendocrine neoplasms (PNENs) has increased due to the widespread use of high-resolution diagnostic imaging in screening programs. Most PNENs are slow-growing indolent neoplasms. However, a local invasion or metastasis can sometimes occur with PNENs, leading to a poor prognosis. The management of small, nonfunctioning PNENs remains under debate. The National Comprehensive Cancer Network guidelines recommend observation in selected cases of small PNENs less than 2 cm. Pancreatic surgery remains a high-risk operation with a 28-30% morbidity and 1% mortality. Therefore, the decision on how to manage small PNENs is challenging. This review focuses on the management of small nonfunctioning PNENs. We also highlight the malignant potential of small PNENs according to tumor size, tumor grade, and tumor biomarker. Endoscopic-ultrasound-guided biopsy is recommended to evaluate the potential risk of malignancy. Furthermore, we discuss the current guidelines and future directions for the management of small PNENs.

Endoscopic ablation therapy for the pancreatic neoplasms

Recently, endoscopic ultrasound (EUS)-guided ablation therapy has been reported as a less invasive therapy for patients with pancreatic neoplasms. Some ablation techniques, including injective ablation (using ethanol or other ablative agents), radiofrequency ablation (RFA), photodynamic therapy, and laser ablation, have been described in the literature. Among these, injective ablation and RFA are more frequently used for treating pancreatic neoplasms. Few studies have evaluated the effectiveness of EUS-guided ethanol ablation (EUS-EA) for potentially malignant solid neoplasms (neuroendocrine neoplasms or solid pseudopapillary neoplasms) and have reported a complete response (CR) rate of 60-80%. In addition, the CR rate after EUS-RFA for these lesions has been reported to be 55-100%, with no additional procedure-related adverse events (AEs). Regarding the amelioration of the symptoms of an insulinoma, the success rates of both the therapies were found to be excellent. Regarding complete tumor ablation, EUS-RFA appeared to be superior to EUS-EA. Although EUS-RFA has been reported as a safe treatment for pancreatic cancers, its effectiveness remains inadequate. Some studies have examined the effectiveness of EUS-guided injection ablation therapy for pancreatic cystic neoplasms (PCNs) and have reported CR rates that range from 35% to 79%. Alcohol-free chemotherapeutic agent ablation appears to be effective, with a low risk of AEs. However, studies on the effectiveness of EUS-RFA for PCNs are limited. In the future, EUS-guided ablation therapy could become a more widely used approach for potentially malignant and malignant pancreatic lesions.