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

Pancreatic cancer precursor lesions - Can immunotherapy prevent progression into pancreatic ductal adenocarcinoma?

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers, with a 5-year survival rate of only 12.5 %. Early detection of PDAC or addressing risk factors for PDAC development are ways to improve outcomes. PDAC can arise from precursor lesions, including pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasm (IPMN), and less frequent, mucinous cystic neoplasm (MCN), and other rare precursor variants. High-risk precursor lesions harbor a substantial chance of evolving into PDAC. Such lesions can often be found in resected PDAC specimens adjacent to the cancer. Unfortunately, recognizing precursor lesions that need to be resected is often tricky, and resections frequently end in major surgical interventions. Thus, better ways to handle precursor lesions are desperately needed. We mapped the immune microenvironments (IMEs) of PanINs, IPMNs, and MCNs on a cellular level using multiplex immunofluorescence and computational imaging technology and compared the findings to PDACs and normal pancreatic tissues. We found distinct and potentially targetable mechanisms of immunosuppression between the two main precursor lesions, PanIN and IMPN. Immunosuppression in IPMNs seems partly mediated by programmed cell death protein 1 ligand (PD-L1) expression on antigen-presenting cells (APCs). By contrast, elevated numbers of regulatory T cells (Tregs) seem to be key players in the immunosuppression of PanINs. Thus, treating high-risk IPMNs with anti-PD-1 and high-risk PanINs with agents targeting Tregs, such as anti-lymphocyte associated protein 4 (anti-CTLA-4) antibodies, could reverse their immunosuppressive state. Reversal of immunosuppression will restore immunosurveillance and eventually prevent progression into PDAC. We also review relevant published and ongoing non-surgical treatment approaches for high-risk IPMNs and PanINs.

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.

Updates on therapeutic endoscopic ultrasound

PURPOSE OF REVIEW

Multiple endoscopic ultrasound (EUS) guided therapeutic interventions have been developed for the management of benign and malignant pancreaticobiliary and gastrointestinal luminal pathology. Recent high-quality evidence is increasingly validating these interventions and positioning them within evidence-based therapeutic algorithms.

RECENT FINDINGS

Here we review therapeutic EUS-guided interventions including pancreatic fluid collection drainage, gastroenterostomy, biliary drainage, pancreatic duct drainage and gallbladder drainage. The most up-to-date high-quality evidence supporting these interventions is presented including comparative data with other conventional treatment options. Newer emerging interventions such as tumor ablation are also reviewed. Current controversies and future avenues for research are discussed. The key role of EUS-guided interventions in managing pancreaticobiliary pathology in patients with a surgically altered anatomy is highlighted.

SUMMARY

Multiple EUS therapeutic interventions have evolved from experimental or rescue options to now well established first- and second-line interventions over other endoscopic, percutaneous and surgical alternatives with the support of high-quality data. Further research is needed to better optimize patient selection and guide long term postintervention follow-up.

Endoscopic Ultrasound-Guided Treatments for Pancreatic Cancer: Understanding How Endoscopic Ultrasound Has Revolutionized Management of Pancreatic Cancer

Pancreatic cancer is associated with high rates of morbidity and mortality. Endoscopic ultrasound (EUS)-guided biopsy has become the standard diagnostic modality per the guidelines. The use of EUS has been growing for providing various treatments in patients with pancreatic cancers: biliary and gallbladder drainage for those with malignant biliary obstruction, gastroenterostomy for malignant gastric outlet obstruction, celiac plexus/ganglia neurolysis for pain control, radiofrequency ablation, placement of fiducial markers, and injection of local chemotherapeutic agents. In this review, we explore the recent clinical studies evaluating the EUS-guided treatments in pancreatic cancer.

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.

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.

Gastroenteropancreatic neuroendocrine neoplasms: epidemiology, genetics, and treatment

The incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP NEN) is increasing at a rapid pace and is becoming an increasingly important consideration in clinical care. Epidemiological data from multiple countries indicate that the incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP NEN) exhibits regional, site-specific, and gender-based variations. While the genetics and pathogenesis of some GEP NEN, particularly pancreatic NENs, have been investigated, there are still many mechanisms that require further investigation. The management of GEP NEN is diverse, but surgery remains the primary option for most cases. Peptide receptor radionuclide therapy (PRRT) is an effective treatment, and several clinical trials are exploring the potential of immunotherapy and targeted therapy, as well as combination therapy.

Efficacy and safety of ultrasound-guided radiofrequency ablation combined with transhepatic artery embolization chemotherapy for hepatocellular carcinoma: A meta-analysis

OBJECTIVE

Meta-analysis was used to assess the efficacy and safety of ultrasound-guided radiofrequency ablation combined with transhepatic artery embolization chemotherapy for hepatocellular carcinoma.

METHODS

Randomized controlled studies on ultrasound-guided radiofrequency ablation combined with transhepatic artery embolization chemotherapy for hepatocellular carcinoma were searched in the databases of PubMed, Embase, Cochrane library, web of science with a search deadline of March 14, 2024. Data were analyzed using Stata 15.0.

RESULT

Six randomized controlled studies involving 520 individuals were finally included, the results of meta-analysis showed that ultrasound-guided radiofrequency ablation combined with TACE can improve objective response rate [RR = 1.52, 95%CI (1.28, 1.81)], improve disease control rate [RR = 1.15, 95%CI (1.06, 1.24)], The survival rate [RR = 1.34, 95%CI (1.19,1.51)] did not increase adverse reactions [RR = 1.34, 95%CI (1.00,1.79)].

CONCLUSION

Based on the findings of the current study, ultrasound-guided radiofrequency ablation combined with TACE was found to improve the objective remission rate, disease control rate, and did not increase adverse events in patients with hepatocellular carcinoma.

Enucleation for Sporadic Nonfunctioning Pancreatic Neuroendocrine Tumors Larger than 2 Centimeters Is Associated with Equivalent Morbidity and Survival Compared to Smaller Tumors: A Multi-Institutional Study

INTRODUCTION

Nonfunctioning pancreatic neuroendocrine tumor (NF-PanNET) ≤2 cm can be observed or resected. Surgery remains recommended for NF-PanNET >2 cm but its extent, enucleation (EN) versus formal resection, remains controversial.

METHODS

Multicentric retrospective cohort of sporadic NF-PanNET patients treated with EN. Short- and long-term outcomes were compared according to tumor size on imaging ≤2 cm versus >2 cm.

RESULTS

131 patients underwent EN for NF-PanNET, including 103 (79.0%) ≤2 cm and 28 (21.0%) >2 cm (extremes, 4-55 mm). Patients' characteristics were comparable, and tumor characteristics only differed in their diameter. Clavien III-IV complications were similar (18.4% vs. 17.9%, p = 1.00) with one death in NF-PanNET ≤2 cm. Grade B/C pancreatic fistula were comparable (16.5% vs. 10.7%, p = 0.850). In NF-PanNET >2 cm there were more pT2/3 stage tumors (85.7% vs. 21.4%, p < 0.001), similar rates of grade G2/3 tumors (25% vs. 16.5%, p = 0.408) with a median Ki67 of 2 (interquartile range: 1-3), and of lymphovascular and perineural invasions. Lymph node picking was done in 46 (35.1%) patients, with a higher median number of harvested lymph nodes in NF-PanNET >2 cm (4 vs. 3, p = 0.01). All were pN0. R0 resection rate (78.6% vs. 82.5%, respectively; p = 0.670) was equivalent. Five-year overall (100% vs. 99%, p = 0.602) and 10-year disease-free (96% vs. 92%, respectively; p = 0.532) survivals were comparable.

CONCLUSIONS

EN for selected NF-PanNET >2 cm carries equivalent morbidity, overall and disease-free survivals compared to those observed with NF-PanNET ≤2 cm.

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

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

Assessing EUS-guided radiofrequency ablation in unresectable pancreatic ductal adenocarcinoma: a single-center historic cohort study

BACKGROUND AND AIMS

EUS-guided radiofrequency ablation (EUS-RFA) has emerged as an alternative for the local treatment of unresectable pancreatic ductal adenocarcinoma (PDAC). We assessed the feasibility and safety of EUS-RFA in patients with unresectable PDAC.

METHODS

This study followed an historic cohort compounded by locally advanced (LA-) and metastatic (m)PDAC-naïve patients who underwent EUS-RFA between October 2019 and March 2022. EUS-RFA was performed with a 19-gauge needle electrode with a 10-mm active tip for energy delivery. Study primary endpoints were feasibility, safety, and clinical follow-up, whereas secondary endpoints were performance status (PS), local control, and overall survival (OS).

RESULTS

Twenty-six patients were selected: 15 with locally advanced pancreatic duct adenocarcinoma (LA-PDAC) and 11 with metastatic pancreatic duct adenocarcinoma (mPDAC). Technical success was achieved in all patients with no major adverse events. Six months after EUS-RFA, OS was seen in 11 of 26 patients (42.3%), with significant PS improvement (P = .03). Local control was achieved, with tumor reduction from 39.5 mm to 26 mm (P = .04). A post-treatment hypodense necrotic area was observed at the 6-month follow-up in 11 of 11 patients who were still alive. Metastatic disease was a significant factor for worsening OS (hazard ratio, 5.021; 95% confidence interval, 1.589-15.87; P = .004).

CONCLUSIONS

EUS-RFA for the treatment of pancreatic adenocarcinoma is a minimally invasive and safe technique that may have an important role as targeted therapy for local treatment of unresectable cases and as an alternative for poor surgical candidates. Also, RFA may play a role in downstaging cancer with a potential increase in OS in nonmetastatic cases. Large prospective cohorts are required to evaluate this technique in clinical practice.

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.

Unraveling the enigma: A comprehensive review of solid pseudopapillary tumor of the pancreas

Solid pseudopapillary tumor of the pancreas (SPTP) is a rare neoplasm predominantly observed in young females. Pathologically, CTNNB1 mutations, β-catenin nuclear accumulation, and subsequent Wnt-signaling pathway activation are the leading molecular features. Accurate preoperative diagnosis often relies on imaging techniques and endoscopic biopsies. Surgical resection remains the mainstay treatment. Risk models, such as the Fudan Prognostic Index, show promise as predictive tools for assessing the prognosis of SPTP. Establishing three types of metachronous liver metastasis can be beneficial in tailoring individualized treatment and follow-up strategies. Despite advancements, challenges persist in understanding its etiology, establishing standardized treatments for unresectable or metastatic diseases, and developing a widely recognized grading system. This comprehensive review aims to elucidate the enigma by consolidating current knowledge on the epidemiology, clinical presentation, pathology, molecular characteristics, diagnostic methods, treatment options, and prognostic factors.

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

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

How to implement adverse events as a quality indicator in gastrointestinal endoscopy

Quality improvement through the registration of endoscopy-related adverse events (AEs) has been recognized by major international endoscopy societies as an important quality indicator. The theory behind this is easier to approve than its implementation in daily practice. The results of many valuable attempts have been published in the literature, mainly highlighting the diverse hurdles trying to capture events related to endoscopy and the sedation used for endoscopic procedures. The current review discusses the difficulties encountered attempting to register AEs and incidents related to endoscopic procedures. Government-driven and financed health-care databases with automated coupling of specific data seem the only efficient way to implement endoscopy-related AEs and outcomes on a prospective and complete basis. This will not only allow continuous confidential feedback to endoscopists in relation to the pooled national benchmark data, but also follow-up in time through data-driven credentialing aiming to progressively optimize these benchmark data.

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.

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.