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

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 ethanol ablation versus surgical resection of insulinomas

PURPOSE

Insulinoma is a rare tumor of the pancreas that can lead to hypoglycemia. To date, the standard therapy is surgical resection. After the first case report of successful endoscopic ultrasound-guided (EUS) ethanol injection 16 years ago, the need for establishing an alternative treatment method remains unchanged given the high morbidity rates of surgery and its unsuitability in some patients.

MATERIALS AND METHODS

Here, we provide retrospective data from 33 insulinoma patients that were treated at our center between 2010 and 2021. Of these, 9 patients were treated with EUS-guided ethanol injection and 24 underwent pancreatic surgery.

RESULTS

The ethanol group was older (ethanol: mean ± SE 67.8±11.2 years vs. surgery: 52.3±15.7, p=0.014) with a higher Charlson Comorbidity Index (3.0 (1.0;4.0) vs. 1.0 (0.0;2.0), p=0.008). The lowest glucose values were similar between groups before (ethanol: 2.09±0.17 mmol/l vs. surgery: 1.81±0.08, p=0.158) and after (4.95±0.74 vs. 5.41±0.28, p=0.581) the respective treatments. Complications occurred more frequently in the surgery group (11 % vs. 54 %, p=0.026). One patient after prior partial pancreatectomy died postoperatively. The hospitalization time was significantly shorter in the ethanol group (4.78±0.78 days vs. 19.88±4.07, p<0.001).

CONCLUSION

EUS-guided ethanol injection can be similarly effective for the treatment of hyperinsulinemic hypoglycemia compared with pancreatic surgery but seems to be associated with less severe complications. This implies the need for prospective randomized trials in insulinoma patients with a low risk for malignancy.

Radiofrequency ablation for the management of symptomatic pancreatic insulinomas

Background and Aims

Insulinomas are among the most common types of functional pancreatic neuroendocrine tumors and can cause debilitating, recurrent, symptomatic hypoglycemia. Pancreatic resection can be curative, but many patients are not candidates for major pancreatic surgery. EUS-guided radiofrequency ablation (EUS-RFA) is a novel minimally invasive technique for ablation of pancreatic tumors.

Methods

In this article and accompanying video, we describe the EUS-RFA ablation device, provide instructions for device setup, and review outcomes of a case series of EUS-RFA for symptomatic insulinomas. We also review the current literature describing EUS-RFA for symptomatic pancreatic insulinomas.

Results

This series of patients in the United States, as well as studies performed in other countries, suggests normalization of insulin levels that appears to be sustained over months to years following the procedure. There has been a favorable adverse event profile in the case series reported to date.

Conclusions

EUS-RFA is emerging as a promising option for the management of symptomatic insulinomas, particularly for patients who are poor surgical candidates or who decline surgery.

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.

Rare Pancreatic/Peripancreatic Cystic Lesions Can Be Accurately Characterized by EUS with Through-the-Needle Biopsy-A Unique Pictorial Essay with Clinical and Histopathological Correlations

Due to their aspecific macroscopic appearance, uncommon pancreatic cystic lesions (PCLs) are often misdiagnosed as mucinous lesions and improperly resected. We aimed to evaluate the endoscopic ultrasound (EUS)-guided through-the-needle biopsy (TTNB) capacity of the preoperative diagnosis of uncommon PCLs. Overall, 136 patients with PCLs who underwent EUS-TTNB between 2016 and 2022 were retrospectively identified. Common histotypes (e.g., IPMN, serous cystadenoma, and mucinous cystadenoma) were excluded and 26 (19.1%) patients (15 female, mean age 52.9 ± 10.4) were analyzed. The EUS findings, adverse events (AEs), and TTNB outcomes in uncommon PCLs were evaluated. The cysts histotype was accurately diagnosed by TTNB in 24/26 (92.3%) cases (seven cystic neuroendocrine tumors, four squamoid cysts, three acinar cells cystadenomas, two lymphoepithelial cysts, two mucinous non-neoplastic cysts, two bronchogenic cysts, two cystic lymphangiomas, one solid-pseudopapillary neoplasm, and one schwannoma). In the remaining two cases, lymphangioma was eventually diagnosed after resection. Surgery was performed in 15/26 (57.7%) patients. The mean follow-up of non-surgical patients was 32.5 months. One severe acute case of pancreatitis (3.8%) that required surgery occurred after EUS-TTNB. Uncommon pancreatic/peripancreatic lesions represent the 19.1% of PCLs in our series, with mainly benign histotypes. TTNB demonstrated a high diagnostic performance with a low rate of AEs in this setting, representing a reliable tool with which to avoid useless surgery.

Epidemiology of Neuroendocrine Neoplasms and Results of Their Treatment with [177Lu]Lu-DOTA-TATE or [177Lu]Lu-DOTA-TATE and [90Y]Y-DOTA-TATE-A Six-Year Experience in High-Reference Polish Neuroendocrine Neoplasm Center

Neuroendocrine neoplasms (NENs) are a group of neoplasms arising from neuroendocrine cells. The worldwide incidence and prevalence of the NENs are estimated to be 6/100,000 and 35/100,000, respectively. Those numbers are increasing every decade, requiring higher and higher diagnosis and treatment costs. Radioligand therapy (RLT) using beta-emitting radioisotopes is an efficient and relatively safe method of treatment, typically used as a second-line treatment. RLT tolerability is higher than other available pharmacotherapies (chemotherapy or tyrosine kinase inhibitors). Recent studies show an increase in overall survival among patients treated with RLT. The present study aimed to learn the epidemiology of NENs in Poland and assess the effectiveness of RLT in a high-reference center. A prospective analysis of 167 patients treated with RLT in one of Poland's highest-reference NEN centers was performed. The analysis covered 66 months of observation (1 December 2017-30 May 2023), during which 479 RLT single administrations of radioisotope were given. The standard procedure was to give four courses of [177Lu]Lu-DOTA-TATE alone, or tandem therapy-[177Lu]Lu-DOTA-TATE and [90Y]Y-DOTA-TATE. Grading analysis showed that most patients had non-functioning G2 NEN with a mean Ki-67 of 6.05% (SD ± 6.41). The most common primary tumor location was the pancreas. Over two-thirds of patients did undergo surgery due to primary tumors or distant metastases. The majority of patients were using lanreotide as a chronically injected somatostatin analog. Median progression-free survival (PFS) on somatostatin analogs was 21.0 (IQR = 29.0) months. Directly after the last course of RLT, disease stabilization was noted in 69.46% of patients, partial regression was noted in 20.36% of patients, complete regression was noted in 0.60% of patients, and progression was noted in 9.58% of patients. In long-term follow-up, the median observation time among patients who underwent four treatment cycles (n = 108) was 29.8 (IQR = 23.9) months. Stabilization of the disease was observed in 55.56% of the patients and progression was observed in 26.85% of the patients, while 17.59% of patients died. Median PFS was 29.3 (IQR 23.9), and the median OS was 34.0 months (IQR 16.0). The mean age of NEN diagnosis is the sixth decade of life. It takes almost three years from NEN diagnosis to the start of RLT. In long-term observation, RLT leads to disease stabilization in over half of the patients with progressive disease. No differences in PFS or OS depend on the radioisotope used for RLT. In Poland, organized coordination of NEN treatment in high-reference centers ensures the continuity of patient care.

Long-term clinical and radiological outcomes of endoscopic ultrasound-guided radiofrequency ablation of benign insulinomas

OBJECTIVE

In recent years, endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) has emerged as an alternative nonsurgical treatment for pancreatic neuroendocrine tumours. The aim of our study was to assess the long-term follow-up of patients treated with EUS-RFA for a sporadic insulinoma in our centre in terms of efficacy, safety and risk of recurrence.

DESIGN, PATIENTS AND MEASUREMENTS

We retrospectively analysed the data of 11 patients with an insulinoma treated by EUS-RFA in our tertiary centre between June 2018 and April 2022. Clinical and biological, as well as imaging, follow-up was planned at 3, 6, 12 months and then annually.

RESULTS

In our series, there were nine women and two men with a median age of 65 years. All tumours were sporadic, with a mean size of 11 mm. The procedure allowed an immediate and complete symptomatic and biological remission in all patients without notable complications. Complete radiological resolution of the tumour after ablation was observed in seven patients, and persistence of an asymptomatic tumour residue was observed in four patients. During the mean follow-up period of 26 months, two patients presented a significant but asymptomatic increase of the tumour residue; a second EUS-RFA session was performed in one patient and the other patient is being closely monitored.

CONCLUSIONS

EUS-RFA treatment of benign insulinomas provides a long-term complete clinical resolution of hypoglycaemia. A long-term follow-up is essential if residual tumour persists after initial EUS-RFA treatment.

Interventional Endoscopic Ultrasound: Current Status and Future Frontiers

Interventional endoscopic ultrasound has fueled remarkable advancements in the field of therapeutic procedures, revolutionizing minimally invasive interventions for a diverse range of conditions. This review highlights the latest breakthroughs and advancements in therapeutic endoscopic ultrasound, showcasing its potential to transform patient care.

Diagnostic Endoscopic Ultrasound in Pancreatology: Focus on Normal Variants and Pancreatic Masses

Background

Endoscopic ultrasound (EUS) is a main tool in gastroenterology for both diagnosis and exclusion of pancreatic pathology. It allows minimally invasive assessment of various diseases or anatomic variations affecting the pancreas also with the help of new Doppler technologies, elastography, contrast-enhanced imaging including post hoc image processing with quantification analyses, three-dimensional reconstruction, and artificial intelligence. EUS also allows interventional direct access to the pancreatic parenchyma and the retroperitoneal space, to the pancreatic duct, pancreatic masses, cysts, and vascular structures.

Summary

This review aimed to summarize new developments of EUS in the field of pancreatology. We highlight the role of EUS in evaluating pancreatic pathology by describing normal anatomic variants like pancreas divisum, pancreatic lipomatosis, pancreatic fibrosis in the elderly and characterizing pancreatic masses, both in the context of chronic pancreatitis and within healthy pancreatic parenchyma. EUS is considered the optimal imaging modality for pancreatic masses of uncertain dignity and allows both cytological diagnosis and histology, which is essential not only for neoplastic conditions but also for tailoring therapy for benign inflammatory conditions.

Key Messages

EUS plays an indispensable role in pancreatology and the development of new diagnostic and interventional approaches to the retroperitoneal space and the pancreas exponentially increased over the last years. The development of computer-aided diagnosis and artificial intelligence algorithms hold the potential to overcome the obstacles associated with interobserver variability and will most likely support decision-making in the management of pancreatic disease.

Study protocol for a multicenter randomized controlled trial to compare radiofrequency ablation with surgical resection for treatment of pancreatic insulinoma

BACKGROUND

Insulinoma is the most common functional pancreatic neuroendocrine tumor and treatment is required to address symptoms associated with insulin hypersecretion. Surgical resection is effective but burdened by high rate of adverse events (AEs). Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) demonstrated encouraging results in terms of safety and efficacy for the management of these tumors. However, studies comparing surgery and EUS-RFA are lacking.

AIMS

The primary aim is to compare EUS-RFA with surgery in term of safety (overall rate of AEs). Secondary endpoints include: (a) severe AEs rate; (b) clinical effectiveness; (c) patient's quality of life; (d) length of hospital stay; (e) rate of local/distance recurrence; (f) need of reintervention; (g) rate of endocrine and exocrine pancreatic insufficiency; (h) factors associated with EUS-RFA related AEs and clinical effectiveness.

METHODS

ERASIN-RCT is an international randomized superiority ongoing trial in four countries. Sixty patients will be randomized in two arms (EUS-RFA vs surgery) and outcomes compared. Two EUS-RFA sessions will be allowed to achieve symptoms resolution. Randomization and data collection will be performed online.

DISCUSSION

This study will ascertain if EUS-RFA can become the first-line therapy for management of small, sporadic, pancreatic insulinoma and be included in a step-up approach in case of clinical failure.

Radiofrequency ablation for pancreatobiliary disease: an updated review

Endoscopic radiofrequency ablation (RFA) has emerged as a minimally invasive treatment option in cases of malignant biliary obstruction, pancreatic cancer, and other pancreatic cystic neoplasms. Intraductal biliary RFA is safe, effective, and confers a survival advantage over stenting alone, where it should be used an adjunct to biliary stenting. Endoscopic ultrasound-guided RFA can also provide pancreatic cyst resolution in patients who are not ideal operative candidates. The aim of this review is to describe the endoscopic applications and associated outcomes of RFA.

Risk factors for EUS-guided radiofrequency ablation adverse events in patients with pancreatic neoplasms: a large national French study (RAFPAN study)

BACKGROUND AND AIMS

EUS-guided radiofrequency ablation (EUS-RFA) has been described as a potentially curative option for solid and cystic pancreatic neoplasms. We aimed to assess the safety and efficacy of pancreatic EUS-RFA in a large study population.

METHODS

A retrospective study retrieving all consecutive patients who underwent pancreatic EUS-RFA during 2019 and 2020 in France was conducted. Indication, procedural characteristics, early and late adverse events (AEs), and clinical outcomes were recorded. Risk factors for AEs and factors related to complete tumor ablation were assessed on univariate and multivariate analyses.

RESULTS

One hundred patients (54% men, 64.8 ± 17.6 years old) affected by 104 neoplasms were included. Sixty-four neoplasms were neuroendocrine neoplasms (NENs), 23 were metastases, and 10 were intraductal papillary mucinous neoplasms with mural nodules. No procedure-related mortality was observed, and 22 AEs were reported. Proximity of pancreatic neoplasms (≤1 mm) to the main pancreatic duct was the only independent risk factor for AEs (odds ratio [OR), 4.10; 95% confidence interval [CI), 1.02-15.22; P = .04). Fifty-nine patients (60.2%) achieved a complete tumor response, 31 (31.6%) a partial response, and 9 (9.2%) achieved no response. On multivariate analysis, NENs (OR, 7.95; 95% CI, 1.66-51.79; P < .001) and neoplasm size <20 mm (OR, 5.26; 95% CI, 2.17-14.29; P < .001) were independently related to complete tumor ablation.

CONCLUSIONS

The results of this large study confirm an overall acceptable safety profile for pancreatic EUS-RFA. Close proximity (≤1 mm) to the main pancreatic duct represents an independent risk factor for AEs. Good clinical outcomes in terms of tumor ablation were observed, especially for small NENs.

When Should We Adopt EUS-Guided Radiofrequency Ablation in Pancreatic Neuroendocrine Tumors?

Pancreatic neuroendocrine neoplasms (PanNENs) are rare and heterogeneous diseases that account for less than 2% of all cases of pancreatic cancer and only 30% of digestive neuroendocrine neoplasia, even if their incidence and prevalence continue to rise globally [...].

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.