Endoscopic ultrasound-guided ethanol ablation therapy for tumors

Comparative Analysis of Surgical and Conservative Approaches to Recurrent Thyroglossal Duct Cysts: A Literature Review

Introduction  The management of recurrent thyroglossal duct cysts poses persistent challenges. The present review assesses chemical ablations and surgical re-interventions as strategies for recurrence. However, limited comparative studies exist to determine the optimal approach and follow-up outcome. Objectives  The aim of the current study is to conduct a review gathering evidence from the literature to analyze and synthesize the safest and most effective approaches for treating recurrent thyroglossal duct cysts. Methods  The present study aims to comprehensively search electronic databases, including the Latin American and Caribbean Literature in Health Sciences (Literatura Latino-Americana e do Caribe em Ciências da Saúde, LILACS, in Portuguese), the database of the Journal of the American Medical Association (JAMA), SciVerse Scopus, Virtual Health Library (Biblioteca Virtual em Saúde, BVS, in Portuguese), and PubMed, for articles on recurrent thyroglossal duct cysts. The selected articles include patients with recurrent cysts, cover publications from 2000 to 2022, describe clinical and/or surgical interventions, and ensure the safety and efficacy of the analyzed approach. Results  The present review included 9 studies, involving a cohort of 278 patients. Out of these patients, 143 underwent surgical interventions and 135 underwent chemical ablations (82 using ethanol and 53 with OK-432). Conclusion  Conservative management of recurrent thyroglossal duct cysts is a growing trend, albeit requiring further refinements. This approach presents potential advantages, including decreased recurrence rates, shorter surgical duration, cost-effectiveness, and expedited recovery. Nevertheless, surgical intervention remains the preferred therapeutic choice owing to its established efficacy and widespread familiarity. The projected therapeutic approach shifts for thyroglossal duct cysts as conservative treatment gains substantiated benefits. Systematic Review Registration : The International Prospective Register of Systematic Reviews (PROSPERO) does not accept scoping reviews, literature reviews, or mapping reviews.

Role of endoscopic ultrasound in the diagnosis and local ablative therapy of pancreatic neuroendocrine tumors

Advancements in diagnostic technology have led to the improved detection of pancreatic neuroendocrine tumors (PNETs) and thus to an increase in the number of reported cases. Endoscopic ultrasound (EUS) technology, including in combination with contrast-enhanced harmonic imaging, aids in distinguishing PNETs from other tumors, while EUS-guided fine-needle aspiration or biopsy has improved the histological diagnosis and grading of tumors. The recent introduction of EUS-guided ablation using ethanol injection or radiofrequency ablation has offered an alternative to surgery in the management of PNETs. Comparisons with surgery have shown similar outcomes but fewer adverse effects. Although standardized protocols and prospective studies with long-term follow-up are still needed, EUS-based methods are promising approaches that can contribute to a better quality of life for PNET patients.

A Solvent Exchange Induced Robust Wet Adhesive Hydrogels to Treat Solid Tumor Through Synchronous Ethanol Ablation and Chemotherapy

The treatment of tumors in developing countries, especially those with poor medical conditions, remains a significant challenge. Herein, a novel solvent-exchange strategy to prepare adhesive hydrogels for the concurrent treatment of tumors through synchronous ethanol ablation and local chemotherapy is reported. First, a poly (gallic acid-lipoic acid) (PGL) ethanol gel is prepared that can undergo solvent exchange with water to form a hydrogel in situ. PGL ethanol gel deposited on the wet tissue can form a hydrogel in situ to effectively repel interfacial water and establish a tight contact between the hydrogel and tissue. Additionally, the functional groups between the hydrogels and tissues can form covalent and non-covalent bonds, resulting in robust adhesion. Furthermore, this PGL ethanol gel demonstrates exceptional capacity to effectively load antitumor drugs, allowing for controlled and sustained release of the drugs locally and sustainably both in vitro and in vivo. In addition, the PGL ethanol gel can combine ethanol ablation and local chemotherapy to enhance the antitumor efficacy in vitro and in vivo. The PGL ethanol gel-derived hydrogel shows robust wet bioadhesion, drug loading, sustained release, good biocompatibility and biodegradability, easy preparation and usage, and cost-effectiveness, which make it a promising bioadhesive for diverse biomedical applications.

Systemic and Local Strategies for Primary Prevention of Breast Cancer

One in eight women will develop breast cancer in the US. For women with moderate (15-20%) to average (12.5%) risk of breast cancer, there are few options available for risk reduction. For high-risk (>20%) women, such as BRCA mutation carriers, primary prevention strategies are limited to evidence-based surgical removal of breasts and/or ovaries and anti-estrogen treatment. Despite their effectiveness in risk reduction, not many high-risk individuals opt for surgical or hormonal interventions due to severe side effects and potentially life-changing outcomes as key deterrents. Thus, better communication about the benefits of existing strategies and the development of new strategies with minimal side effects are needed to offer women adequate risk-reducing interventions. We extensively review and discuss innovative investigational strategies for primary prevention. Most of these investigational strategies are at the pre-clinical stage, but some are already being evaluated in clinical trials and others are expected to lead to first-in-human clinical trials within 5 years. Likely, these strategies would be initially tested in high-risk individuals but may be applicable to lower-risk women, if shown to decrease risk at a similar rate to existing strategies, but with minimal side effects.

Evolution of Pancreatic Endotherapy

In the last half century, endotherapy for pancreatic diseases has changed considerably. Although endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasound (EUS) were introduced initially as diagnostic tools, they quickly evolved into therapeutic tools for preventing and managing complications of pancreatitis. More recently, therapeutic endoscopy has shown potential in palliation and cure of pancreatic neoplasms. This article discusses the changing landscape of pancreatic endotherapy as therapeutic ERCP and EUS were introduced and because they have evolved to treat different diseases.

Mammary duct luminal epithelium controls adipocyte thermogenic programme

Sympathetic activation during cold exposure increases adipocyte thermogenesis via the expression of mitochondrial protein uncoupling protein 1 (UCP1)1. The propensity of adipocytes to express UCP1 is under a critical influence of the adipose microenvironment and varies between sexes and among various fat depots2-7. Here we report that mammary gland ductal epithelial cells in the adipose niche regulate cold-induced adipocyte UCP1 expression in female mouse subcutaneous white adipose tissue (scWAT). Single-cell RNA sequencing shows that glandular luminal epithelium subtypes express transcripts that encode secretory factors controlling adipocyte UCP1 expression under cold conditions. We term these luminal epithelium secretory factors 'mammokines'. Using 3D visualization of whole-tissue immunofluorescence, we reveal sympathetic nerve-ductal contact points. We show that mammary ducts activated by sympathetic nerves limit adipocyte UCP1 expression via the mammokine lipocalin 2. In vivo and ex vivo ablation of mammary duct epithelium enhance the cold-induced adipocyte thermogenic gene programme in scWAT. Since the mammary duct network extends throughout most of the scWAT in female mice, females show markedly less scWAT UCP1 expression, fat oxidation, energy expenditure and subcutaneous fat mass loss compared with male mice, implicating sex-specific roles of mammokines in adipose thermogenesis. These results reveal a role of sympathetic nerve-activated glandular epithelium in adipocyte UCP1 expression and suggest that mammary duct luminal epithelium has an important role in controlling glandular adiposity.

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.

X-Ray Visualization of Intraductal Ethanol-Based Ablative Treatment for Prevention of Breast Cancer in Rat Models

There are still a limited number of primary interventions for prevention of breast cancer. For women at a high risk of developing breast cancer, the most effective intervention is prophylactic mastectomy. This is a drastic surgical procedure in which the mammary epithelial cells that can give rise to breast cancer are completely removed along with the surrounding tissue. The goal of this protocol is to demonstrate the feasibility of a minimally invasive intraductal procedure that could become a new primary intervention for breast cancer prevention. This local procedure would preferentially ablate mammary epithelial cells before they can become malignant. Intraductal methods to deliver solutions directly to these epithelial cells in rodent models of breast cancer have been developed at Michigan State University and elsewhere. The rat mammary gland consists of a single ductal tree that has a simpler and more linear architecture compared to the human breast. However, chemically induced rat models of breast cancer offer valuable tools for proof-of-concept studies of new preventive interventions and scalability from mouse models to humans. Here, a procedure for intraductal delivery of an ethanol-based ablative solution containing tantalum oxide nanoparticles as X-ray contrast agent and ethyl cellulose as gelling agent into the rat mammary ductal tree is described. Delivery of aqueous reagents (e.g., cytotoxic compounds, siRNAs, AdCre) by intraductal injection has been described previously in mouse and rat models. This protocol description emphasizes methodological changes and steps that pertain uniquely to delivering an ablative solution, formulation consideration to minimize local and systemic side effects of the ablative solution, and X-ray imaging for in vivo assessment of ductal tree filling. Fluoroscopy and micro-CT techniques enable to determine the success of ablative solution delivery and the extent of ductal tree filling thanks to compatibility with the tantalum-containing contrast agent.

Role of endoscopic ultrasound in vascular interventions: Where are we now?

From a mere diagnostic tool to an imperative treatment modality, endoscopic ultrasound (EUS) has evolved and revolutionized safer efficient options for vascular interventions. Currently it is an alternative treatment option in the management of gastrointestinal bleeding, primarily variceal type bleeding. Conventional treatment option prior to EUS incorporation had limited efficiency and high adverse events. The characterization and detail provided by EUS gives a cutting edge towards a holistically successful management choice. Data indicates that EUS-guided combination therapy of coil embolization and glue injection has the higher efficacy for the treatment of varices. Conversely, similar treatment options that exist for esophageal and other ectopic variceal bleeding was also outlined. In conclusion, many studies refer that a combination therapy of coil and glue injection under EUS guidance provides higher technical success with fewer recurrence and adverse events, making its adaptation in the guideline extremely favorable. Endo-hepatology is a novel disciple with a promising future outlook, we reviewed topics regarding portal vein access, pressure gradient measurement, and thrombus biopsy that are crucial interventions as alternative of radiological procedures. The purpose of this review is to provide an update on the latest available evidence in the literature regarding the role of EUS in vascular interventions. We reviewed the role of EUS in variceal bleeding in recent studies, especially gastric varices and novel approaches aimed at the portal vein.

Intraductal Delivery and X-ray Visualization of Ethanol-Based Ablative Solution for Prevention and Local Treatment of Breast Cancer in Mouse Models

Breast cancer is the most prevalent cancer and the second-leading cause of cancer-related death for women in the USA. For high-risk women, prophylactic mastectomy is the most effective primary prevention strategy. Prophylactic mastectomy is an aggressive surgical procedure that completely removes the mammary epithelial cells from which breast cancer arises along with the surrounding tissue. We seek to develop a minimally invasive intraductal procedure as an alternative to prophylactic mastectomy to locally ablate the mammary epithelial cells before they can become malignant. We and others have developed an intraductal delivery procedure to reach and treat these epithelial cells in rodent models of breast cancer. While the mouse mammary gland with a single non-anastomosed ductal tree opening at the nipple has a much less complex and tortuous architecture than the human breast, chemically induced and genetically engineered mouse models of breast cancer are valuable to produce proof-of-concept studies of new preventative strategies. Here, we describe a procedure for intraductal delivery of an ethanol-based ablative solution containing micro-CT/X-ray tantalum-based contrast agent within the mouse mammary ductal tree for the therapeutic purpose of primary prevention of breast cancer. Intraductal delivery of aqueous reagents (e.g., cytotoxic compounds, siRNAs, AdCre) has been previously described in mouse models. Thus, we focus our protocol description on methodological modifications and unique experimental considerations for optimizing delivery of ethanol, for minimizing local and systemic side effects of ethanol administration, and for in vivo visualization of ductal tree filling via micro-CT/fluoroscopy imaging. Visualization of the ductal tree immediately after injection of a contrast-containing solution allows for confirmation of complete filling or unsuccessful outcomes such as underfilling or overfilling. This procedure can be applied for delivery and imaging of other ablative compounds aimed at either preventing tumor formation or locally treating early-stage tumors accessible via the ductal tree.

Endoscopic ultrasound role in pancreatic adenocarcinoma treatment: A review focusing on technical success, safety and efficacy

The impressive technological advances in recent years have rapidly translated into the shift of endoscopic ultrasound (EUS) from diagnostic modality into an interventional and therapeutic tool. Despite the great advance in its diagnosis, the majority of pancreatic adenocarcinoma cases are inoperable when diagnosed, thus demanding alternative optional therapies. EUS has emerged as an easy, minimally invasive modality targeting this carcinoma with different interventions that have been reported recently. In this review we summarize the evolving role of interventional therapeutic EUS in pancreatic adenocarcinoma management.

Temulence Therapy to Orthotopic Colorectal Tumor via Oral Administration of Fungi-Based Acetaldehyde Generator

Taking inspiration from percutaneous ethanol injection (PEI) for tumor ablation, an acetaldehyde generator (SC@ZIF@ADH) is constructed for tumor treatment by modifying a metal-organic framework nanocarrier (ZIF), which is loaded with alcohol dehydrogenase (ADH), onto the surface of Saccharomyces cerevisiae (SC). Oral administration of SC@ZIF@ADH can target tumor via mannose-mediated targeting to tumor associated macrophages (TAMs) and generate ethanol at the hypoxic tumor areas. Ethanol is subsequently catalyzed to toxic acetaldehyde by ADH, inducing tumor cells apoptosis and polarizing TAMs toward the anti-tumor phenotype. In vivo animal results show that this acetaldehyde generator can cause a temulence-like reaction in the tumor, significantly inhibiting tumor progression, and might provide an intelligent and nonsurgical substitute for PEI therapy.

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.

Radiologic-pathologic analysis of increased ethanol localization and ablative extent achieved by ethyl cellulose

Ethanol provides a rapid, low-cost ablative solution for liver tumors with a small technological footprint but suffers from uncontrolled diffusion in target tissue, limiting treatment precision and accuracy. Incorporating the gel-forming polymer ethyl cellulose to ethanol localizes the distribution. The purpose of this study was to establish a non-invasive methodology based on CT imaging to quantitatively determine the relationship between the delivery parameters of the EC-ethanol formulation, its distribution, and the corresponding necrotic volume. The relationship of radiodensity to ethanol concentration was characterized with water-ethanol surrogates. Ex vivo EC-ethanol ablations were performed to optimize the formulation (n = 6). In vivo ablations were performed to compare the optimal EC-ethanol formulation to pure ethanol (n = 6). Ablations were monitored with CT and ethanol distribution volume was quantified. Livers were removed, sectioned and stained with NADH-diaphorase to determine the ablative extent, and a detailed time-course histological study was performed to assess the wound healing process. CT imaging of ethanol-water surrogates demonstrated the ethanol concentration-radiodensity relationship is approximately linear. A concentration of 12% EC in ethanol created the largest distribution volume, more than eight-fold that of pure ethanol, ex vivo. In vivo, 12% EC-ethanol was superior to pure ethanol, yielding a distribution volume three-fold greater and an ablation zone six-fold greater than pure ethanol. Finally, a time course histological evaluation of the liver post-ablation with 12% EC-ethanol and pure ethanol revealed that while both induce coagulative necrosis and similar tissue responses at 1-4 weeks post-ablation, 12% EC-ethanol yielded a larger ablation zone. The current study demonstrates the suitability of CT imaging to determine distribution volume and concentration of ethanol in tissue. The distribution volume of EC-ethanol is nearly equivalent to the resultant necrotic volume and increases distribution and necrosis compared to pure ethanol.

Surgical outcomes are hampered after endoscopic ultrasonography-guided ethanol lavage and/or Taxol injection in cystic lesions of the pancreas

BACKGROUNDS/AIMS

Endoscopic ultrasonography-guided ethanol lavage and Taxol injection (EUS-ELTI) for pancreatic cystic lesions have been recently performed in some medical centers. The aim of this study was to optimize patient selection and analyze outcomes of patients who underwent surgeries after EUS-ELTI for pancreatic cystic lesions.

METHODS

Among 310 patients who underwent EUS-ELTI between January 2007 and December 2014, 23 underwent surgeries after EUS-ELTI owing to incomplete treatment and/or adverse events. Surgical outcomes of patients who underwent surgeries after EUSELTI were evaluated. Clinical outcomes of patients who underwent surgeries after EUS-ELTI were then retrospectively compared with those of patients who underwent upfront surgery for left-sided pancreatic lesions without an EUS-ELTI procedure.

RESULTS

The pathology revealed degenerated cysts in 12 patients, mucinous cyst neoplasms in five, neuroendocrine tumors in two, intraductal papillary mucinous neoplasm (IPMN) in one, solid pseudopapillary tumor in one, pancreatic ductal adenocarcinoma arising from an IPMN in one, and hepatoid carcinoma in one. Twelve patients underwent laparoscopic distal pancreatectomy and five patients underwent open distal pancreatectomy. When clinical outcomes were retrospectively compared between patients who underwent laparoscopic distal pancreatectomy after EUS-ELTI and those who did not receive an EUS-ELTI procedure, the spleen-preserving rate was 0% in the EUS-ELTI group and 61.7% (365/592) in the control group (p < 0.001).

CONCLUSIONS

Surgical outcomes are compromised after EUS-ELTI for cystic tumor of the pancreas. Further studies are needed to investigate the efficacy and safety of the EUS-ELTI procedure.

The overview of the deep learning integrated into the medical imaging of liver: a review

Deep learning (DL) is a recently developed artificial intelligent method that can be integrated into numerous fields. For the imaging diagnosis of liver disease, several remarkable outcomes have been achieved with the application of DL currently. This advanced algorithm takes part in various sections of imaging processing such as liver segmentation, lesion delineation, disease classification, process optimization, etc. The DL optimized imaging diagnosis shows a broad prospect instead of the pathological biopsy for the advantages of convenience, safety, and inexpensiveness. In this paper, we reviewed the published representative DL-related hepatic imaging works, described the general situation of this new-rising technology in medical liver imaging and explored the future direction of DL development.

Diagnostic and Interventional Role of Endoscopic Ultrasonography for the Management of Pancreatic Neuroendocrine Neoplasms

Pancreatic neuroendocrine neoplasms (PanNENs) are relatively rare, but their incidence has increased significantly in the last decades. Precise diagnosis and prognostic stratification are crucial for proper patient management. Endoscopic ultrasound (EUS) is the modality of choice for diagnosis of solid pancreatic tumors, showing a higher tumor detection rate than other imaging modalities, especially for small size lesions. EUS also serves as a guide for preoperative sampling and other interventions. EUS-tissue acquisition is a safe and highly accurate technique for cyto/histological diagnosis of PanNENs with a well-demonstrated correlation between Ki-67 proliferation index values and tumor grading on EUS and surgical specimens according to the WHO 2017 classification. Furthermore, the possibility of a preoperative EUS-guided fine needle tattooing or fiducial markers placement may help the surgeon to locate small and deep tumors, thus avoiding formal pancreatic resections in favor of parenchymal-sparing surgery. Finally, locoregional ablative treatments using either ethanol injection or radiofrequency ablation have been proposed in recent studies with promising results in order to control symptoms or reduce tumor burden in selected patients unfit for surgery with functioning or non-functioning PanNENs. This article review highlights the current role of EUS in PanNENs management, focusing on the present and future applications of EUS-guided interventions.

EUS-guided ablation of pancreatic neoplasms

Ablative therapies for locoregional treatment of pancreatic neoplastic lesions developed over the last decade to be applied during surgery are now becoming also available to be utilized under endoscopic ultrasound (EUS) guidance. The advantage of this approach is clear because of the close proximity of the EUS transducer to the target lesion, coupled with developments of specifically designed ablation devices, making the procedure minimally invasive, and potentially sparing patients from the morbidity of this method when performed surgically. EUS-guided ablative techniques that have been applied to pancreatic neoplastic cysts, pancreatic functional and non-functional neuroendocrine neoplasms and pancreatic ductal adenocarcinoma include ethanol injection, radiofrequency ablation (RFA), a combination of bipolar RFA and cryoablation, laser therapy (LT) and photodynamic therapy (PDT). Up to now, most of these procedures have been applied to patients at high surgical risk or who refused surgery. However, more studies evaluating some of these treatments also in selected patients not at surgical risk are becoming available. These studies will pave the road to apply this therapeutic approach to a more extensive number of patients, alone or in association with other therapies, such as immunomodulating drugs. The present manuscript will critically review the available evidence in the field of EUS-guided local ablative treatment of solid and cystic pancreatic neoplasms.

Endoscopic ultrasound-guided therapies for pancreatic solid tumors: An overview

The close proximity of the endoscopic ultrasound (EUS) probe to the pancreas, coupled with the ease with which a needle can be inserted into a pancreatic lesion, have contributed to the development of EUS-guided therapies for both adenocarcinoma and neuroendocrine pancreatic neoplasms. EUS-guided fine needle injection of different types of drugs, implantation of fiducial markers to facilitate stereotactic body radiation therapy or of radioactive seeds to perform brachytherapy, and the use of different thermal and nonthermal ablation devices and techniques have all been tested in preliminary human studies. This manuscript will present the available evidence accumulated thus far in the field of EUS-guided oncological treatment of pancreatic solid tumors, along with a look into possible future applications.

Interventional endoscopic ultrasound for pancreatic neuroendocrine neoplasms

The proximity of the endoscopic ultrasound (EUS) transducer to the pancreas and the possibility to place needles or other accessories into a target located adjacent to the wall of the GI tract have encouraged researchers to develop various EUS-guided local treatments directed towards pancreatic neuroendocrine neoplasms (PanNENs). The use of pre-operative EUS-guided tattooing or fiducial marker placement to facilitate intraoperative tumor localization has proven effective in reducing operative time of laparoscopic surgeries. To reduce the mortality and morbidity rates of surgical resection, which is presently the mainstay treatment of PanNENs. EUS-guided loco-regional treatments, such as injection of alcohol and radiofrequency ablation have been proposed and results are hitherto promising. The present paper summarizes currently available data in the field of EUS-guided interventions to pancreatic neuroendocrine tumors, as well as possible future applications.

Alcohol-Mediated Renal Sympathetic Neurolysis for the Treatment of Hypertension: The Peregrine™ Infusion Catheter

Renal sympathetic denervation using conventional non-irrigated radiofrequency catheters has potential technical shortcomings, including limited penetration depth and incomplete circumferential nerve damage, potentially impacting therapeutic efficacy. Against this background, second generation multi-electrode, radiofrequency and ultrasound renal denervation systems have been developed to provide more consistent circumferential nerve ablation. Irrigated catheters may allow deeper penetration while minimizing arterial injury. In this context, catheter-based chemical denervation, with selective infusion of alcohol, a potent neurolytic agent, into the perivascular space, may minimize endothelial, intimal and medial injury while providing circumferential neurolysis. Animal studies demonstrate pronounced renal norepinephrine level reductions and consistent renal nerve injury after perivascular alcohol infusion using the Peregrine Catheter. Early clinical studies demonstrated significant blood pressure reductions and a reasonable safety profile. Randomized sham-controlled trials (NCT03503773, NCT02910414) are underway to examine whether the aforementioned theoretical advantages of alcohol-medicated denervation with the Peregrine System™ Kit translate into clinical benefits.

Endoscopic ultrasound in chronic liver disease

Endoscopic ultrasound (EUS) is a minimally invasive diagnostic and therapeutic modality with a number of established as well as evolving uses in patients with chronic liver disease. Compared to other diagnostic tools such as cross-sectional imaging or conventional endoscopy, EUS has been shown to increase diagnostic sensitivity and therapeutic success for many clinical scenarios and applications with a low rate of adverse events. In this review, we discuss and focus on the current and growing role of EUS in the evaluation and/or treatment of hepatobiliary masses, hepatic parenchymal disease, portal hypertension, esophageal and other varices, and indeterminate biliary strictures.

Endoscopic ultrasound-guided injective ablative treatment of pancreatic cystic neoplasms

With the development of cross-sectional imaging modalities and the increasing attention being paid to physical examinations, the prevalence of pancreatic cystic neoplasms (PCNs) has increased. PCNs comprise a broad differential spectrum with some PCNs having low or no malignant potential and others having high malignant potential. The morbidity and mortality rates related to major pancreatic surgical resection are high. Long-term surveillance may not only increase the financial burden and psychological stress for patients but also result in a missed malignancy. Minimally invasive endoscopic ultrasound (EUS)-guided ethanol ablation was first reported in 2005. Several other agents, such as paclitaxel, lauromacrogol, and gemcitabine, were reported to be effective and safe for the treatment of PCNs. These ablative agents are injected through a needle inserted into the cyst via transgastric or transduodenal puncture. This treatment method has been substantially developed in the last 15 years and is regarded as a promising treatment to replace surgical resection for PCNs. While several reviews of EUS-guided ablation have been published, no systematic review has evaluated this method from patient preparation to follow-up in detail. In the present review, we systematically describe EUS-guided injective ablation with regard to the indications, contraindications, preoperative treatment, endoscopic procedure, postoperative care and follow-up, evaluation method, treatment efficiency, safety profile, tips and tricks, and current controversies and perspectives.

Ductal tree ablation by local delivery of ethanol prevents tumor formation in an aggressive mouse model of breast cancer

Background

Prophylactic mastectomy is the most effective intervention to prevent breast cancer. However, this major surgery has life-changing consequences at the physical, emotional, psychological, and social levels. Therefore, only high-risk individuals consider this aggressive procedure, which completely removes the mammary epithelial cells from which breast cancer arises along with surrounding tissue. Here, we seek to develop a minimally invasive procedure as an alternative to prophylactic mastectomy by intraductal (ID) delivery of a cell-killing solution that locally ablates the mammary epithelial cells before they become malignant.

Methods

After ID injection of a 70% ethanol-containing solution in FVB/NJ female animals, ex vivo dual stained whole-mount tissue analysis and in vivo X-ray microcomputed tomography imaging were used to visualize ductal tree filling, and histological and multiplex immunohistochemical assays were used to characterize ablative effects and quantitate the number of intact epithelial cells and stroma. After ID injection of 70% ethanol or other solutions in cancer-prone FVB-Tg-C3(1)-TAg female animals, mammary glands were palpated weekly to establish tumor latency and examined after necropsy to record tumor incidence. Statistical difference in median tumor latency and tumor incidence between experimental groups was analyzed by log-rank test and logistic mixed-effects model, respectively.

Results

We report that ID injection of 70% ethanol effectively ablates the mammary epithelia with limited collateral damage to surrounding stroma and vasculature in the murine ductal tree. ID injection of 70% ethanol into the mammary glands of the C3(1)-TAg multifocal breast cancer model significantly delayed tumor formation (median latency of 150 days in the untreated control group [n = 25] vs. 217 days in the ethanol-treated group [n = 13], p value < 0.0001) and reduced tumor incidence (34% of glands with tumors [85 of 250] in the untreated control group vs. 7.3% of glands with tumor [7 of 95] in the ethanol-treated group, risk ratio = 4.76 [95% CI 1.89 to 11.97, p value < 0.0001]).

Conclusions

This preclinical study demonstrates the feasibility of local ductal tree ablation as a novel strategy for primary prevention of breast cancer. Given the existing clinical uses of ethanol, ethanol-based ablation protocols could be readily implemented in first-in-human clinical trials for high-risk individuals.

EUS-guided ethanol ablation therapy for gastric stromal tumors

EUS-guided fine-needle ethanol injection (FNI) therapy of some types of cystic and solid tumors has been documented. However, reported cases to date of gastrointestinal-stromal tumors (GIST) treated with this technique are scarce. Ethanol ablation is an alternative treatment with a low rate of adverse events in selected cases.

Treatment response and preliminary efficacy of hepatic tumour laser ablation under the guidance of percutaneous and endoscopic ultrasonography

Background

Studies focusing on the treatment effectiveness of endoscopic ultrasonography (EUS)-guided laser ablation (LA) for hepatic tumours or the technical differences from percutaneous ultrasonography (US)-guided LA are lacking. The objective of this study was to evaluate the treatment response and preliminary efficacy of US- and EUS-guided LA for hepatic tumours.

Methods

We performed a prospective analysis of treatment response and preliminary efficacy in 92 consecutive patients who underwent US-LA and EUS-LA from January 2015 to June 2017. The primary endpoint was complete tumour ablation (CTA). The secondary endpoint was 12-month local tumour progression (LTP).

Results

Among a total of 120 hepatic lesions, 20 lesions were ablated under the guidance of EUS. The application of the multi-fibre technique (0, 0% vs. 69, 69.0%, p < 0.01), tumours located in the left lobe (18, 90.0% vs. 28, 28.0%, p < 0.01) and multi-session ablation (4, 20.0% vs. 4, 4.0%, p = 0.009) were factors found to be significantly different between the EUS-LA and US-LA groups. The CTA was achieved in 94% of patients in the US-LA group and 100% of patients in the EUS-LA group (p = 0.261). Twelve-month LTP was observed in 8.5% of the patients in the US-LA group and 15.0% of the patients in the EUS-LA group with no significant difference between the two groups (p = 0.372). The multivariate analysis identified that the tumour diagnosis (p = 0.004; 95% CI, 0.039–0.547) was the only independent risk factor associated with 12-month LTP.

Conclusions

Patients in the EUS-LA and US-LA groups shared as similar treatment response and preliminary efficacy in the treatment of hepatic tumours. A hybrid LA approach to nonsurgical hepatic tumours appeared to be reasonable.

Endoscopic ultrasonography (EUS)-guided laser ablation (LA) of adrenal metastasis from pancreatic adenocarcinoma

Endoscopic ultrasonography (EUS)-guided laser ablation (LA) is potentially applicable to tumours in the left lobe of the liver and pancreas. This report seeks to introduce the novel use of EUS-guided LA for left adrenal metastases from pancreatic adenocarcinoma. A 70-year-old female was referred to our hospital for dull abdominal pain and tiredness for 1 month. Computed tomography (CT) discovered a 1.0 × 1.7 cm mass in the area of the left adrenal gland. The lesion was highly suspicious for metastasis due to her history of pancreatic adenocarcinoma 1 year ago, which was removed through radical surgery. Intraoperative frozen-section pathology revealed a tumour invading the left adrenal gland. The left adrenal mass was clearly visualised on EUS and exhibited irregular hyper-enhancement during contrast. The tumour was successfully treated by four sessions of EUS-guided LA. After the procedure, symptomatic relief was achieved and remained. At the 4-month follow-up, contrast-enhanced CT revealed that the volume of the target was significantly decreased. Here, we introduced a new method for left adrenal metastasis using thermal ablation through EUS. As a potential alternative access to the percutaneous approach, EUS-guided LA may provide a minimally invasive treatment to relieve the tumour burdens and symptoms when applied accurately.

Non-surgical ablative therapies for inoperable benign insulinoma

PURPOSE

Benign insulinoma is the most common functioning neuroendocrine tumor of the pancreas. The gold-standard therapeutic approach for insulinoma is surgery, which allows for tumor removal, histology and immunochemical analyses. If surgery is not feasible, minimally invasive ablative procedures performed by interventional radiology can lead to partial or complete remission of hormone hypersecretion and tumor control in insulinoma patients.

METHODS

We performed a review of existing literature on non-chemotherapeutic/radioactive ablative techniques employed for the treatment of benign, otherwise inoperable, pancreatic insulinoma. For this purpose, feasibility, effectiveness and safety of ablative treatments for pancreatic insulinoma were reviewed from literature data published from 1982 to date.

RESULTS

A total of 44 insulinoma cases treated with non-surgical ablative techniques were desumed, and divided as follows: 7 cases of tumor embolization, 26 ethanol ablations, 7 radiofrequency ablations, 2 high intensity focused ultrasound ablation, 1 irreversible electroporation and 1 percutaneous microwave ablation. Most cases involved single insulinoma, predominantly located in the pancreas head and body. In the majority of patients, ablation was chosen instead of surgery due to severe comorbidities. After an average follow-up of 16 months, the overall success rate of non-surgical ablative treatments of insulinoma was 84%, the recurrence/persistence rate was 16%, and transient adverse events were noted in 23% of cases. Adverse events were usually self-limiting and medically manageable.

CONCLUSIONS

Non-surgical ablation is a feasible, safe and repeatable procedure in patients with pancreatic insulinoma, who are not candidate to surgery or refuse it. Partial or complete control of symptoms and tumor growth is experienced by the majority of patients.

Gastrointestinal stromal tumors: a comprehensive review

Gastrointestinal stromal tumors (GISTs) are rare neoplasms of the gastrointestinal tract associated with high rates of malignant transformation. Most GISTs present asymptomatically. They are best identified by computed tomography (CT) scan and most stain positive for CD117 (C-Kit), CD34, and/or DOG-1. There have been many risk stratification classifications systems which are calculated based on tumor size, mitotic rate, location, and perforation. The approaches to treating GISTs are to resect primary low-risk tumors, resect high-risk primary or metastatic tumors with imatinib 400 mg daily for 12 months, or if the tumor is unresectable, neoadjuvant imatinib 400 mg daily followed by surgical resection is recommended. Sunitinib is required for KIT exon 9, 13, and 14 mutations, while ponatinib is used for exon 17 mutations and regorafenib for highly refractory tumors. High-risk tumors should be monitored for recurrence with serial abdominal CT scans. Radiofrequency ablation has shown to be effective when surgery is not suitable. Newer therapies of ipilimumab, nivolumab, and endoscopic ultrasound alcohol ablation have shown promising results. This report addresses the epidemiology, clinical presentation, diagnostic imaging, histologic diagnosis, classification and risk stratification, staging and grading, surgical treatment, adjuvant treatment, and metastasis of GISTs.

Endoscopic ultrasound-guided ethanol ablation therapy for pancreatic insulinoma: an unusual strategy

Summary

Insulinomas are the most frequent cause of hyperinsulinaemic hypoglycaemia. Although surgical enucleation is the standard treatment, a few other options are available to high-risk patients who are elderly or present with co-morbidities. We present a case report of an 89-year-old female patient who was admitted to the emergency department due to recurrent hypoglycaemia, especially during fasting. Laboratory work-up raised the suspicion of hyperinsulinaemic hypoglycaemia, and abdominal CT scan revealed a 12 mm nodular hypervascular lesion of the pancreatic body suggestive of neuroendocrine tumour. The patient was not considered a suitable candidate for surgery, and medical therapy with diazoxide was poorly tolerated. Endoscopic ultrasound-guided ethanol ablation therapy was performed and a total of 0.6 mL of 95% ethanol was injected into the lesion by a transgastric approach; no complications were reported after the procedure. At 5 months of follow-up, no episodes of hypoglycaemia were reported, no diazoxide therapy was necessary, and revaluation abdominal CT scan revealed a pancreatic nodular lesion with a size involution of about half of its original volume. The patient is regularly followed-up at the endocrinology clinic and shows a significant improvement in her wellbeing and quality of life.

Learning points:

Efficacy and safety of endoscopic ultrasonography-guided interventional treatment for refractory malignant left-sided liver tumors: a case series of 26 patients

This study aimed to compare the efficacy and safety of EUS-guided ethanol injection and ¹²⁵I seed brachytherapy for malignant left-sided liver tumors which were difficult for trans-abdominal intervention. The study protocol was registered at Clinicaltrials.gov (NCT02816944). Twenty-six patients were consecutively and prospectively hospitalized for EUS-guided interventional treatment of refractory malignant left-sided liver tumors between June 2014 and June 2016. Liver masses were detected using EUS in 25 of 26 (96.2%) patients. EUS-guided interventional treatment was completed uneventfully in 23 of 26 (88.5%) patients using anhydrous ethanol injection (n = 10) or iodine-125 seed implantation (n = 13). Six months later, complete response was achieved in 15 of 23 (65.2%) patients and partial response in 8 of 23 (34.8%) patients. Patients with tumor residual have second-look EUS-guided interventional treatment (n = 5), radiotherapy (n = 2) or surgical resection (n = 1). Complete response was achieved after repeated interventional treatment in 3 of 5 patients who underwent second EUS-guided intervention; 2 patients required additional surgical resection but one succeed. No significant complications occurred. Therefore EUS-guided ¹²⁵I seed brachytherapy is an effective and safe treatment modality for radical operation or promising palliative control of malignant left-sided liver tumors refractory to trans-abdominal intervention.

Irreversible electroporation for the treatment of pancreatic neuroendocrine tumors

Backgrounds/Aims

Resection or enucleation is currently the treatment of choice for small pancreatic neuroendocrine tumors (NETs). Irreversible electroporation is a novel ablative method that is used for locally advanced pancreatic adenocarcinoma, but little data exists for its use for pancreatic NETs. We report an early experience of IRE for early pancreatic NETs.

Methods

Between April 2014 and March 2015, 3 patients with small (<2 cm) pancreatic NETs were treated with percutaneous IRE.

Results

There were no adverse effects during the procedure. Mean hospital stay was 2.6 days. All patients remained disease free on 12-19 months follow up. One patient developed recurrent pancreatitis with pseudocyst formation.

Conclusions

IRE for small tumors of the pancreas is practical and may offer advantages over other thermal ablative techniques, since it preserves vital structures such as blood vessels, bile and pancreatic ducts. Further data regarding the long term disease free interval is required to establish efficacy.

Time-dependent image changes after ethanol injection into the pancreas: an experimental study using a porcine model

BACKGROUND

Ethanol, a commonly available agent, has been used to successfully ablate cystic and solid lesions in the pancreas. The aim of this study is to investigate the effects of an ethanol injection into the porcine pancreas and observe the time-dependent image changes in the pancreatic parenchyma.

METHODS

Pure ethanol was injected into the pancreatic tail using a 25-gauge EUS needle with direct ultrasound guidance under celiotomy: 1 mL and 2 mL were injected, respectively. The abdomen was closed after the injection. MRI was performed before the procedure, immediately after, and on postoperative day (POD) seven. Blood samples were taken before the procedure and on PODs one, three, five, and seven. The pigs were euthanised on POD seven.

RESULTS

Immediately after the injection, linear high signal areas in the pancreatic tail on T2 and rounded speckled high signal areas on DWI images were detected in both animals, measuring 35 × 32 mm in the 1 mL injected pig and 42 × 38mm in the 2 mL injected pig. After POD seven, rounded high signal areas were noted on T2 images, measuring 22 × 18 mm and 36 × 28 mm respectively. On POD one, the 1 mL injected animal had a 53% elevation in serum amylase while the 2 mL injected animal had a 66% elevation. Histologically, cystic and necrotic changes in the parenchyma were observed, measuring 23 × 22 mm and 40 × 35 mm respectively.

CONCLUSIONS

Our results, which are limited to normal pancreas, suggested that a 1 mL injection caused localised changes within the pancreas while a 2 mL injection induced more widespread changes beyond the pancreas. The effective area of ethanol was widespread immediately after injection, and then the area was reduced with cystic and necrosis changes.

Endoscopic ultrasound-guided ethanol ablation of pancreatic neuroendocrine tumours: A case study and literature review

Here we offer a review of the literature regarding endoscopic ultrasound-guided ethanol ablation for pancreatic neuroendocrine tumours and describe the case of a cystic tumour completely ablated after a multisession procedure. A total of 35 PubMed indexed cases of treated functioning and non-functioning pancreatic neuroendocrine tumours resulted from our search, 29 of which are well-documented and summarised. Endoscopic ultrasound-guided ethanol ablation appears as a local, minimally invasive treatment of pancreatic neuroendocrine tumours, suitable for selected patients. This technique appears feasible, relatively safe and efficient, especially when applied to symptom relief in functioning tumours, aiming at loss of endocrine secretion. For non-functioning tumours, where the goal is complete tissue ablation, eus guided ethanol ablation can provide good results for patients who are unfit for surgery or for those who refuse surgical resection. Its role in “fit for surgery” patients requires assessment through further studies.

Safety and Efficacy of EUS-Guided Ethanol Ablation for Treating Small Solid Pancreatic Neoplasm

The strategy for treating small borderline malignant pancreatic neoplasms--such as neuroendocrine tumor (NET) and solid pseudopapillary neoplasm (SPN)--is surgical resection. However, pancreatic resection of these lesions still causes significant morbidity. We evaluated the safety and efficacy of EUS-guided ethanol ablation to treat small solid pancreatic neoplasms. A total of 8 patients with small borderline malignant pancreatic neoplasms and co-morbidities who refused surgery were included. We identified 2 cases of nonfunctioning NET, 3 cases of insulinomas, 1 case of gastrinoma, and 2 cases of SPN. EUS-guided ethanol ablation was performed, and treatment outcomes were assessed with clinical symptom, hormone assay, and imaging study. The mean tumor diameter was 15  mm (range, 7-29  mm), and the median volume of injected ethanol was 2.8  mL (range, 1.2-10.5  mL). There was 1 severe acute pancreatitis after EUS-guided ethanol ablation with 20-gauge CPN needle. During follow-up (median 16.5 months), 6 patients achieved treatment success; however, 2 patients (1 nonfunctioning NET and 1 SPN) still had persistent tumors. The patient with persistent SPN underwent surgical resection and the histopathological results showed peripancreatic infiltration with perineural invasion. Among 6 patients who achieved initial treatment success, 1 patient experienced tumor recurrence within 15 months and underwent repeated EUS-guided ethanol ablation. In conclusion, EUS-guided ethanol ablation therapy is a promising option for patients with small solid pancreatic neoplasm. Multiple sessions or surgical interventions may be required if there is a recurrent or persistent mass, and procedure-related adverse events must be carefully monitored.

Therapeutic role of endoscopic ultrasound in pancreaticobiliary disease: A comprehensive review

With the development of technology and accessories, the role of endoscopic ultrasound (EUS) has evolved from diagnostics to therapeutics. In order to characterise the therapeutic role of EUS, we searched Web of Knowledge database and reviewed articles associated with therapeutic EUS. There are two modalities for the therapeutic purpose: drainage and fine-needle injection. EUS-guided drainage is a promising procedure for the treatment of peripancreatic fluid collection and biliary obstruction; EUS-guided fine-needle injections such as celiac plexus neurolysis, for the purpose of pain relief for pancreatic cancer and chronic pancreatitis, has emerged as a promising procedure. The aim of the study was to perform a comprehensive and conscientious review on the techniques, complications and clinical outcomes of those EUS-based procedures.

Minimally Invasive Techniques for Resection of Pancreatic Neuroendocrine Tumors

Surgical resection remains the treatment of choice for primary pancreatic neuroendocrine tumors (PNETs), because it is associated with increased survival. Minimally invasive procedures are a safe modality for the surgical treatment of PNETs. In malignant PNETs, laparoscopy is not associated with a compromise in terms of oncologic resection, and provides the benefits of decreased postoperative pain, better cosmetic results, shorter hospital stay, and a shorter postoperative recovery period. Further prospective, multicenter, randomized trials are required for the analysis of these minimally invasive surgical techniques for the treatment of PNETs and their comparison with traditional open pancreatic surgery.

Ethanol Ablation of a Peripheral Nerve Sheath Tumor Presenting as a Small Bowel Obstruction

Ethanol has historically been used as an ablative agent for a variety of lesions. One of the more common applications of this technique is celiac plexus neurolysis; however, recent reports have suggested a role for the endoscopic alcohol ablation of a variety of solid and cystic lesions. We report a novel case of endoscopic ethanol ablation of a peripheral nerve sheath tumor presenting as a small bowel obstruction.

Using the Promise of Sonodynamic Therapy in the Clinical Setting against Disseminated Cancers

Sonodynamic therapy (SDT) is a form of ultrasound therapy in which specialized chemotherapeutic agents known as sonosensitizers are administered to increase the efficacy of ultrasound-mediated preferential damage of neoplastic cells. Multiple in vitro and in vivo studies have indicated that SDT has the ability to exhibit profound physical and chemical changes on cellular structure. As supportive as the data have been, assessment of this method at the clinical level has been limited to only solid tumors. Although SDT has shown efficacy against multiple adherent neoplastic cell lines, it has also shown particular promise with leukemia-derived cell lines. Potential procedures to administer SDT to leukemia patients are heating the appendages as ultrasound is applied to these areas (Heat and Treat), using an ultrasound probe to scan the body for malignant growths (Target and Destroy), and extracorporeal blood sonication (EBS) through dialysis. Each method offers a unique set of benefits and concerns that will need to be evaluated in preclinical mammalian models of malignancy before clinical examination can be considered.

Success of endoscopic ultrasound-guided ethanol ablation of pancreatic cysts: a meta-analysis and systematic review

BACKGROUND

Endoscopic ultrasound (EUS)-guided ethanol ablation has emerged as an efficacious and safe alternative management option for pancreatic cysts. We undertook a meta-analysis and systematic review to assess the overall safety and efficacy of EUS-guided ethanol ablation of pancreatic cysts.

METHOD STUDY SELECTION CRITERIA

EUS-guided ethanol ablation of pancreatic cysts.

DATA COLLECTION EXTRACTION

Articles were searched in Medline, Pubmed, and Ovid journals.

STATISTICAL METHOD

Fixed and random effects models were used to calculate the pooled proportions.

RESULTS

Initial search identified 1,319 reference articles, in which 120 relevant articles were selected and reviewed. Data was extracted from seven studies (n = 152) of EUS-guided ethanol ablation of pancreatic cysts, which met the inclusion criteria. With EUS-guided ethanol ablation, the pooled proportion of patients with complete cyst resolution was 56.20 % (95 % CI = 48.16 to 64.08) and partial cyst resolution was 23.72 % (95 % CI = 17.24 to 30.89). Postprocedural complications after ablation were significant for abdominal pain in 6.51 % (95 % CI = 3.12 to 11.04) and pancreatitis in 3.90 % (95 % CI = 1.39 to 7.60) of the pooled percentage of patients. Publication bias calculated using Harbord-Egger bias indicator gave a value of -1.09 (95 % CI = 10.21 to 8.03, p = 0.77). The Begg-Mazumdar indicator gave a Kendall's tau b value of 0.05 (p ≥ 0.99).

CONCLUSIONS

EUS-guided ethanol ablation may be a safe alternative treatment modality for pancreatic cysts, with acceptable intraprocedural and postprocedural complications. However, due to the limited data available, prospective randomized controlled trials with a long follow up period are required in this area.

Endoscopic ultrasonography-guided ethanol ablation for small pancreatic neuroendocrine tumors: results of a pilot study

Background/Aims

Endoscopic ultrasonography (EUS)-guided ethanol ablation is gaining popularity for the treatment of focal pancreatic lesions. The aim of this study was to evaluate the safety, feasibility, and treatment response after EUS-guided ethanol injection for small pancreatic neuroendocrine tumors (p-NETs).

Methods

This was a retrospective analysis of a prospectively collected database including 11 consecutive patients with p-NETs who underwent EUS-guided ethanol injection.

Results

EUS-guided ethanol injection was successfully performed in 11 patients with 14 tumors. The final diagnosis was based on histology and clinical signs as follows: 10 non-functioning neuroendocrine tumors and four insulinomas. During follow-up (median, 370 days; range, 152 to 730 days), 10 patients underwent clinical follow-up after treatment, and one patient was excluded because of loss to follow-up. A single treatment session with an injection of 0.5 to 3.8 mL of ethanol resulted in complete responses (CRs) at the 3-month radiologic imaging for seven of 13 tumors (response rate, 53.8%). Multiple treatment sessions performed in three tumors with residual viable enhancing tissue increased the number of tumors with CRs to eight of 13 (response rate, 61.5%). Mild pancreatitis occurred in three of 11 patients.

Conclusions

EUS-guided ethanol injection appears to be a safe, feasible, and potentially effective method for treating small p-NETs in patients who are poor surgical candidates.

Endoscopic ultrasound-guided ethanol ablation of a large metastatic carcinoid tumor: success with a note of caution

Endoscopic ultrasonography with fine needle infusion (EUS-FNI) of alcohol is the most reported method for EUS-guided tumor ablation. Several studies have reported successful EUS-guided ablation of pancreatic neuroendocrine tumors. However, these tumors have been relatively small (< 3 cm). In this report, a 50-year-old man with a metastatic carcinoid tumor with a large porta hepatis mass was referred to our clinic for EUS-guided ethanol ablation. After two separate EUS-FNI ablations, there was a 36 % reduction in tumor size (9.0 × 11.4 cm to 6.7 × 9.8 cm) with associated tumor lysis syndrome. Chromogranin A levels decreased from 460 to 132 ng/mL. The patient reported complete resolution of abdominal pain within 2 weeks, but only mild improvement in flushing and diarrhea. In conclusion, large metastatic neuroendocrine tumors can be successfully treated with EUS-guided ethanol ablation. Evidence-based guidelines are needed with regard to the appropriate volume of ethanol injected in EUS-guided ablation to promote the efficacy and safety of this emerging procedure.

Endoscopic diagnosis and treatment of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PNETs) are rare pancreatic neoplasms comprising only 1% to 2% of all pancreatic tumors. In recent years, the number of incidentally discovered PNETs has greatly increased given the widespread use of axial imaging. However, a significant proportion of PNETs may not be visualized on conventional imaging such as computed tomography, magnetic resonance imaging, and somatostatin receptor scintigraphy. Endoscopic ultrasound (EUS) has become an integral part of the diagnosis of PNETs because of its high sensitivity for detecting, localizing, and diagnosing PNETs. EUS-guided tissue acquisition provides histologic and immunologic confirmation, and may also allow prognostication about tumor behavior. In addition to preoperative assessment of these tumors, EUS has also been shown to have an important role in nonoperative management of small nonfunctional PNETs. Finally, recent developments suggest that interventional EUS may be used to aid intraoperative localization of PNETs and to deliver therapeutic agents for the treatment of PNETs. This review will discuss the endoscopic diagnosis and treatment of PNETs, with focus on recent advances in the utility of EUS in the clinical management of these tumors.

The role of therapeutic endoscopic ultrasound now and for the future

Therapeutic endoscopic ultrasound (EUS) became possible after the advent of the linear echoendoscope and the EUS guided fine needle aspiration. Over the past two decades, the indications for therapeutic EUS have expanded and evidence regarding its utility has been steadily accumulating. Randomized studies have shown EUS to be effective for cancer pain relief (celiac plexus neurolysis), pancreatic fluid collection drainage, and biliary drainage. Prospective studies have shown EUS-guided biliary drainage to be safe and effective in patients with failed ERCP. There is evidence to suggest that EUS is effective for pancreatic duct drainage, gallbladder drainage, and drainage of pelvic collections. EUS may also be useful for targeted cancer treatment via brachytherapy, radiofrequency ablation, or injection therapy. Therapeutic EUS is likely to play an increasingly important role in endoscopic therapy of gastrointestinal diseases in the near future.

EUS-guided ethanol ablation of insulinomas: case series and literature review

Surgical resection is a standard treatment for insulinomas; however, it is associated with a high risk of complications and limited to specific suitable candidates. In recent years, endoscopic ultrasound (EUS)-guided ethanol ablation of insulinomas has emerged as a new therapeutic option, especially for elderly patients and candidates unfit for surgery. We aimed to evaluate the feasibility and safety of this technique for insulinomas. Four patients diagnosed with insulinomas based on EUS-fine-needle aspiration and immunohistochemistry results underwent EUS-guided 95% ethanol ablation. A comprehensive literature review was performed to understand the current status of the feasibility, safety, and effects of EUS-guided ethanol ablation of insulinomas. EUS-guided ethanol ablation of insulinomas was successfully completed in all the 4 patients. There were no perioperative or postoperative complications. The patients were discharged at 3 days after the procedure. No recurrence of hypoglycemia or tumors was noted during follow-up (range, 3-6 months). Literature review showed 8 patients with insulinomas who underwent EUS-guided ethanol ablation. All the procedures were successful, with no need for further surgical treatment. Among these reviewed cases, 6 patients had no post-procedural complications, while other 2 patients showed a mild increase in the serum levels of lipase and/or pancreatic enzymes within 48 h post-procedure; furthermore, 1 of these 2 patients presented at a later date with medically controllable hematoma and ulceration. During follow-up, 6 patients remained asymptomatic and normoglycemic, while the 2 patients who presented post-procedural complications developed occasional mild confusion. EUS-guided ethanol ablation of insulinomas is an effective and safe modality, with an acceptable level of post-procedural complications. However, the long-term effects of this new therapeutic option need to be validated in a large randomized controlled trial with longer follow-up.