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

Efficacy and safety of endoscopic ultrasonography-guided ethanol injections of small pancreatic neuroendocrine neoplasms: a prospective multicenter study

Endoscopic ultrasonography (EUS)-guided ethanol injection (EI) has recently been introduced as one of the management strategies for pancreatic neuroendocrine neoplasms (PNENs); however, its role as a surgical alternative is unclear. We evaluated the efficacy and safety of EUS-EI in treating small PNENs through a prospective multicenter study.Patients with grade 1 tumors of ≤15 mm confirmed by pathology were included. The primary end point assessed efficacy and safety, measuring complete ablation using computed tomography at 1 and 6 months, prevention of adverse events (AEs) within 1 month, severe pancreatic fistula at 1 month, and incidence/worsening of diabetes mellitus (DM) at 6 months. The composite end point of EUS-EI was compared with that of historical results of a study based on surgical treatment.25 patients with PNENs, with a median tumor size of 10.1 mm, were treated using EUS-EI. The composite primary end point was achieved by 76.0% of patients (19/25; 95%CI 54.9%-90.6%), a proportion significantly higher than that of surgical treatment (P = 0.008). Regarding efficacy, 88.0% (22/25) of patients achieved complete ablation at 1 and 6 months (95%CI 68.8%-97.5%). Regarding safety, 96.0% (24/25) of patients had no severe AEs within 1 month (95%CI 79.7%-99.9%). No patients had severe pancreatic fistulas at 1 month, and 84.0% (21/25) had no incidence or exacerbation, or both, of DM at 6 months (95%CI 63.9%-95.5%).EUS-EI is safe and could be a potent treatment option for patients with small PNENs.

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 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.

What Is the Latest in Pancreatic Cysts?

Pancreatic cysts are common incidental findings. The understanding of pancreatic cysts has evolved tremendously over the past few decades. Molecular diagnostic and endoscopic techniques have led to more precise characterization of cyst types and interventions to improve patient outcomes. This article outlines these recent innovations in pancreatic cyst diagnosis and management.

Endoscopic Ultrasound-Guided Locoregional Treatments for Pancreatic Neuroendocrine Neoplasms

Pancreatic neuroendocrine neoplasms (pNENs) represent approximately 2% of all solid pancreatic tumors. The incidence of pNENs has been increasing in the last decade. The clinical manifestations of pNENs range from hormone secretion syndromes in functioning neoplasms (F-pNENs) to local infiltration or distant metastases in late-stage diagnoses or incidental findings in small non-functioning neoplasms (NF-pNENs). While surgery is the gold-standard treatment for larger and more aggressive tumors, small and low-grade tumors (G1) may be followed-up due to the indolent course of disease. Recently, endoscopic ultrasound (EUS)-guided ablative techniques, such as ethanol injection (EUS-EI) and radiofrequency ablation (EUS-RFA), have emerged as promising options for loco-regional ablations in selected cases. Despite promising safety profile and efficacy, high-quality evidence is needed to support their widespread adoption. This article reviews the current state of EUS-guided locoregional therapies, patient selection criteria, procedural details, and associated risks.

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.

Pancreatic Neuroendocrine Neoplasms: Classification and Novel Role of Endoscopic Ultrasound in Diagnosis and Treatment Personalization

The incidence and prevalence of pancreatic neuroendocrine neoplasms are steadily increasing. These tumors are highly heterogeneous, with treatment options ranging from observation to surgery, and various medical therapies. The choice of treatment is influenced by factors such as tumor stage, grade (proliferative activity), and the presence of hormone-related syndromes. Endoscopic ultrasound (EUS) is becoming increasingly valuable for assessing pancreatic neuroendocrine neoplasms, offering detailed morphological, vascular, and functional information through techniques such as contrast enhancement and elastography. It also allows biopsies that are useful for both histopathological and molecular analyses. These tumors are highly heterogeneous, with treatment options ranging from observation to various medical therapies and surgery. Recent data suggest that small, non-functioning PanNENs with low proliferation rates may be safely monitored, whereas more aggressive or functioning tumors typically require surgery. EUS-guided ablation is a promising alternative for patients with functional pancreatic neuroendocrine neoplasms who are unsuitable for surgery, although randomized trials are needed. In non-resectable pancreatic neuroendocrine neoplasms, treatment options include somatostatin analogs, targeted therapies (e.g., everolimus, sunitinib), chemotherapy, and radioligand therapy. This review discusses key factors in planning personalized treatment strategies for pancreatic neuroendocrine neoplasms.

Long‑term survival after comprehensive treatment in a patient with advanced neuroendocrine neoplasm of the pancreas: A case report

Neuroendocrine neoplasms of the pancreas (pNENs) are rare. In February 2021, a 54-year-old woman was diagnosed with pNEN and multiple metastases within the liver. The patient, diagnosed with grade G2 neuroendocrine neoplasm (T4N0M1), underwent an ultrasonography-guided liver biopsy and radiofrequency ablation. After receiving Sandostatin LAR in April 2021, side effects led to its discontinuation after seven cycles. Following two sessions of radiofrequency ablation, the patient's condition was stable. However, disease progression was noted in September 2023, resulting in hemodialysis and closed peritoneal drainage. Surufatinib was administered, stabilizing the tumor by November 2023. The patient underwent transarterial chemoembolization due to a large tumor burden, with subsequent MRCP showing stability from diagnosis in February 2021 to June 2024. The present case report highlights the role of tailored treatment strategies considering patient comorbidities and tumor biology, and the significance of secondary puncture biopsy, which, despite not being pursued by the patient in the present study due to the associated risks, may provide survival benefits for patients with advanced or metastatic pNEN.

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

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

EUS-guided radiofrequency ablation for pancreatic adenocarcinoma

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

EUS-Guided Radiofrequency Ablation Therapy for Pancreatic Neoplasia

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

Diagnosis and Management of Pancreatic Cysts

As pancreatic cyst incidence rises, likely due to the ubiquitous increase in cross-sectional imaging, their management presents multiple challenges for both the practitioner and patient. It is critical that all pancreatic cysts are appropriately characterized, as treatment decisions depend on an accurate diagnosis. Diagnostic modalities such as cytology, biopsy, and cyst fluid biomarkers allow for definitive diagnosis of virtually all lesions. Some cysts, such as intraductal papillary mucinous neoplasms, mucinous cystic neoplasms, and cystic pancreatic endocrine neoplasms, have malignant potential and must be surveyed. Other cysts, such as serous cystadenomas and pancreatic fluid collections, do not have malignant potential. Surveillance strategies vary widely depending on cyst type and size and while multiple medical societies advocate surveillance, their published surveillance guidelines are heterogenous. Cysts with high-risk stigmata or worrisome features are usually resected, depending on the patient's surgical fitness. In patients unfit for resection, newer endoscopic ablative techniques are advocated. Controversial aspects regarding cyst management include whether surveillance can be stopped, how surveillance should be performed, and the extensive financial burden cyst management places on the health care system. Further study into the natural history of cystic lesions, including definitive determination of the rate of malignant transformation for each cyst type, is essential.

The Assessment of a Novel Endoscopic Ultrasound-Compatible Cryocatheter to Ablate Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease that may be treated utilizing thermal therapies. Cryoablation is an effective, minimally invasive therapy that has been utilized for the treatment of various cancers, offering patients a quicker recovery and reduced side effects. Cryoablation has been utilized on a limited basis for the treatment of PDAC. With the recent reports on the success of cryoablation, there is a growing interest in the use of cryoablation as a standalone, minimally invasive procedure to treat PDAC. While offering a promising path, the application of cryoablation to PDAC is limited by current technologies. As such, there is a need for the development of new devices to support advanced treatment strategies for PDAC. To this end, this study investigated the performance of a new endoscopic ultrasound-compatible cryoablation catheter technology, FrostBite. We hypothesized that FrostBite would enable the rapid, effective, minimally invasive delivery of ultra-cold temperatures to target tissues, resulting in effective ablation via an endoscopic approach. Thermal properties and ablative efficacy were evaluated using a heat-loaded gel model, tissue-engineered models (TEMs), and an initial in vivo porcine study. Freeze protocols evaluated included single and repeat 3 and 5 min applications. Isotherm assessment revealed the generation of a 2.2 cm diameter frozen mass with the -20 °C isotherm reaching a diameter of 1.5 cm following a single 5 min freeze. TEM studies revealed the achievement of temperatures ≤ -20 °C at a diameter of 1.9 cm after a 5 min freeze. Fluorescent imaging conducted 24 h post-thaw demonstrated a uniformly shaped ellipsoidal ablative zone with a midline diameter of 2.5 cm, resulting in a total ablative volume of 6.9 cm3 after a single 5 min freeze. In vivo findings consistently demonstrated the generation of ablative areas measuring 2.03 cm × 3.2 cm. These studies demonstrate the potential of the FrostBite cryocatheter as an endoscopic ultrasound-based treatment option. The data suggest that FrostBite may provide for the rapid, effective, controllable freezing of cancerous pancreatic and liver tissues. This ablative power also offers the potential of improved safety margins via the minimally invasive nature of an endoscopic ultrasound-based approach or natural orifice transluminal endoscopic surgery (NOTES)-based approach. The results of this pre-clinical feasibility study show promise, affirming the need for further investigation into the potential of the FrostBite cryocatheter as an advanced, minimally invasive cryoablative technology.

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.