Endoscopic ultrasound-guided radiofrequency ablation: A game-changer in pancreatic cancer treatment

Abstract

Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) has emerged as a promising minimally invasive treatment option for pancreatic cancer, offering precision and reduced morbidity compared to traditional surgical methods. Recent technological advancements, such as refined monopolar and bipolar electrodes and integrated cooling systems, have significantly improved the precision and safety of EUS-RFA, enabling effective treatment for various pancreatic lesions, including pancreatic ductal adenocarcinoma, pancreatic neuroendocrine tumors, and cystic lesions. Clinical outcomes demonstrate high technical success rates, with tumor size reduction and symptom palliation, particularly in patients with unresectable or high-risk pancreatic cancer. The combination of EUS-RFA with chemotherapy has shown enhanced tumor control and potentially improved survival, although long-term benefits remain uncertain. Emerging evidence highlights the immunomodulatory effects of EUS-RFA, suggesting its potential to augment systemic anti-tumor immunity, especially when combined with immunotherapies. Despite these promising findings, the role of EUS-RFA in the overall management of pancreatic cancer is still evolving, with limited large-scale randomized trials. Standardization of procedural protocols, patient selection criteria, and comparative effectiveness data are critical areas for future research to solidify EUS-RFA's position in pancreatic cancer treatment.

Key Words: Endoscopic ultrasound-guided radiofrequency ablation; Pancreatic cancer; Pancreatic ductal adenocarcinoma; Pancreatic neuroendocrine tumors; Immunomodulatory effects; Tumor ablation

Core Tip: Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is a promising minimally invasive treatment for pancreatic cancer, particularly in patients with unresectable or high-risk tumors. Recent technological advancements have improved procedural precision and safety, demonstrating high technical success rates and potential symptom palliation. When combined with chemotherapy, EUS-RFA may offer enhanced tumor control and survival benefits, though long-term clinical outcomes require further investigation. Additionally, the immunomodulatory effects of EUS-RFA may augment systemic anti-tumor immunity, offering a potential synergy with immunotherapies. However, larger randomized controlled trials and standardized protocols are needed to fully establish its role in the clinical management of pancreatic cancer.

INTRODUCTION

Pancreatic cancer is one of the most aggressive malignancies, with a five-year survival rate of less than 10%, making it one of the deadliest cancers worldwide[1,2]. The majority of patients present with advanced or unresectable disease at the time of diagnosis, and only a small subset of patients is eligible for curative surgical resection[1,3]. Surgical resection remains the only potentially curative treatment but is feasible in fewer than 20% of cases, highlighting the need for alternative therapies that can effectively manage or control the disease[1,3].

Over the past two decades, radiofrequency ablation (RFA) has emerged as a promising minimally invasive therapy for pancreatic cancer, evolving from intraoperative and percutaneous techniques to endoscopic ultrasound-guided RFA (EUS-RFA). EUS-RFA allows for precise targeting of pancreatic lesions using real-time imaging, minimizing damage to adjacent healthy tissues and reducing procedural morbidity[4,5]. This development has significantly expanded the potential applications of RFA, which is now used not only for treating liver tumors but also for pancreatic neuroendocrine tumors, cystic lesions, and pancreatic ductal adenocarcinoma[4,6].

Despite these advancements, the management of pancreatic cancer remains a formidable challenge. The disease's aggressive biology, dense stromal microenvironment, and resistance to conventional therapies complicate treatment efforts[7,8]. While EUS-RFA has demonstrated technical feasibility and safety in various studies, there remains a lack of consensus regarding its long-term efficacy, optimal patient selection, and its comparative effectiveness against other standard treatments[6,9,10]. Furthermore, controversies persist about the extent of survival benefits, the immunomodulatory effects of the procedure, and the adverse event profiles, with some studies reporting promising outcomes and others indicating limited impact on overall survival (OS)[6,11]. These uncertainties have led to confusion in clinical guidelines and have contributed to the underutilization of this potentially valuable therapeutic modality[3,12].

TECHNOLOGICAL INNOVATIONS IN EUS-RFA

One of the primary advancements in RFA for pancreatic cancer has been the integration of EUS-RFA, which significantly enhances the precision of tumor targeting. EUS-RFA allows for real-time imaging guidance, enabling clinicians to precisely localize the tumor and ablate it with minimal impact on surrounding healthy tissues[4,6]. The overall workflow and biological effects of EUS-RFA are illustrated in Figure 1. The development of specialized monopolar and bipolar electrode systems has further improved RFA's precision and safety, making it possible to treat tumors that were previously considered inoperable or high-risk for conventional surgery[1,5]. Bipolar systems, in particular, allow for more controlled and localized ablation, reducing the risk of thermal injury to adjacent organs[13]. These technological innovations also include systems with internal cooling mechanisms, which help to prevent collateral damage and improve procedural safety[1].

Figure 1 Endoscopic ultrasound-guided radiofrequency ablation in pancreatic cancer treatment. This diagram illustrates the process of endoscopic ultrasound-guided radiofrequency ablation in pancreatic cancer, including the technology used for precise tumor targeting, the biological effects such as thermal injury and immune activation, clinical outcomes like tumor reduction and improved survival, and future prospects for combining endoscopic ultrasound-guided radiofrequency ablation with chemotherapy and immunotherapy. OS: Overall survival; PDAC: Pancreatic ductal adenocarcinoma; PFS: Progression-free survival; PNET: Pancreatic neuroendocrine tumor; RCT: Randomised controlled trial; RF: Radiofrequency.

Furthermore, advancements in RFA probe technology have enabled better targeting and more efficient delivery of energy. For instance, the use of probes with tailored energy settings and the development of probes with integrated cooling systems have improved the procedure's overall efficiency, reduced complications, and increased tumor necrosis rates[1,14]. These developments are critical for increasing the procedural success rates of EUS-RFA and expanding its applications to a wider range of pancreatic lesions, including not only pancreatic ductal adenocarcinoma but also pancreatic neuroendocrine tumors and cystic lesions[4,6].

Despite these advances, there is still a lack of consensus on optimal RFA protocols, including energy levels, ablation duration, and the frequency of sessions[1,6]. The variability in RFA devices and settings between different centers complicates direct comparisons of outcomes and hinders the development of standardized procedural guidelines[4]. Additionally, although the integration of cooling systems and more advanced energy modulation has reduced some of the risks associated with thermal injury, further improvements in device precision and operator training are needed to minimize adverse events, particularly in tumors located near critical structures[15,16].

CLINICAL OUTCOMES AND SAFETY PROFILES

Clinical studies on EUS-RFA have consistently demonstrated high technical success rates, with some studies reporting rates of up to 99%[9]. Clinical success, defined as tumor size reduction or necrosis, has been observed in approximately 85% to 90% of patients[4]. EUS-RFA has shown particular promise in providing symptom relief, especially in terms of pain management, and improving the quality of life for patients with unresectable pancreatic cancer[4,9]. These findings are significant, as pancreatic cancer is often associated with severe pain and discomfort, particularly in the advanced stages.

In addition to symptom palliation and tumor cytoreduction, emerging evidence suggests that EUS-RFA may also contribute to downstaging borderline resectable pancreatic tumors, thereby increasing the feasibility of subsequent radical surgical resection in selected patients[17]. Although current data remain preliminary and mostly derived from small cohorts or case series, several reports have shown partial tumor shrinkage and improved vascular clearance after RFA, indicating its potential role as an adjunct to neoadjuvant strategies[18].

In terms of safety, EUS-RFA has a favorable safety profile. The most commonly reported adverse events include mild to moderate abdominal pain and pancreatitis, both of which are generally self-limited and manageable[9,19]. More severe complications, such as perforation or bleeding, are rare and occur in fewer than 5% of cases[9]. This makes EUS-RFA an attractive alternative for patients who are high surgical risks or have tumors that are otherwise not amenable to surgical resection[19].

However, despite these promising results, the long-term clinical benefits of EUS-RFA remain unclear. While some studies report improved survival rates in patients treated with EUS-RFA in combination with chemotherapy[20], the evidence remains limited, and further research is needed to establish the definitive role of EUS-RFA in extending survival. The need for more randomized controlled trials with longer follow-up periods is critical to determine the long-term efficacy of EUS-RFA in pancreatic cancer treatment[1,2].

Importantly, not all studies have demonstrated favorable or meaningful clinical benefits. Several reports have shown only modest tumor response or no significant extension in OS, particularly in patients with advanced disease or large tumor burden[21]. These less favorable findings highlight that EUS-RFA is not universally effective and that its clinical benefit may depend strongly on tumor biology, stage, and procedural factors. Incorporating these results ensures a balanced perspective and underscores the need for cautious interpretation of existing evidence.

COMPARATIVE EFFECTIVENESS OF EUS-RFA

EUS-RFA has been compared with other treatment modalities, such as chemotherapy, surgery, and other locoregional therapies, to assess its effectiveness in managing pancreatic cancer. The combination of EUS-RFA with chemotherapy has shown encouraging results, particularly in terms of improving tumor control and reducing the need for pain medication. Some studies suggest that this combination may lead to improved OS and progression-free survival compared to chemotherapy alone[20]. Median OS in patients receiving EUS-RFA combined with chemotherapy has been reported to range from 20.5 months to 24.03 months[20], which is promising compared to historical controls.

Beyond survival benefits, EUS-RFA has also been investigated as a potential tool for downstaging borderline resectable pancreatic cancer[22]. By reducing tumor volume or decreasing encasement of major vascular structures, RFA may facilitate conversion to resectability when used alongside established neoadjuvant regimens[23,24]. Although evidence remains limited, initial data support its potential utility as a complementary locoregional therapy in this clinical context.

In comparison to surgical resection, EUS-RFA offers a less invasive option with reduced morbidity and mortality. While surgery remains the gold standard for resectable pancreatic tumors, EUS-RFA provides a valuable option for patients who are ineligible for surgery due to comorbidities or tumor location[1,25]. However, more direct comparisons between EUS-RFA and other locoregional therapies, such as microwave ablation (MWA) or irreversible electroporation (IRE), are needed to assess its relative efficacy[15,16]. Ongoing trials like the PELICAN trial are evaluating the role of EUS-RFA combined with chemotherapy vs chemotherapy alone, which will provide more clarity on the overall effectiveness of this combination[12].

In addition to these preliminary comparisons, several studies have contrasted EUS-RFA directly with other emerging ablative modalities[26]. MWA, for instance, can achieve higher intratumoral temperatures and larger, more uniform ablation zones, but its application near major vascular structures may increase the risk of collateral injury[27]. In contrast, EUS-RFA offers more controlled and localized thermal delivery with real-time endoscopic visualization, making it potentially safer for lesions embedded within complex pancreatic anatomy[28].

IRE, another frequently compared modality, is nonthermal and therefore preserves the integrity of surrounding vasculature and ductal tissues[29]. While this makes IRE attractive for tumors encasing major vessels, it requires general anesthesia with neuromuscular blockade and is associated with higher procedural complexity[30]. EUS-RFA, by comparison, can be performed under moderate sedation or deep sedation and involves shorter procedural time, though its ablation field is generally smaller[31].

Overall, these comparative data suggest that each modality – EUS-RFA, MWA, and IRE – possesses unique strengths and limitations. EUS-RFA stands out for its minimally invasive endoscopic access, real-time visualization, and relatively low complication rates, whereas MWA and IRE may be preferable in selected anatomic or tumor-specific scenarios. Continued head-to-head research will be critical for refining optimal treatment algorithms and patient selection.

IMMUNOMODULATORY EFFECTS OF EUS-RFA

Emerging evidence suggests that EUS-RFA has potential immunomodulatory effects that may enhance systemic anti-tumor immunity. RFA induces localized tumor destruction, which results in the release of tumor antigens, thereby activating the immune system and potentially leading to an abscopal effect, where immune responses target distant tumor sites[7,32]. This is particularly relevant in pancreatic cancer, where the tumor microenvironment is highly immunosuppressive, and traditional treatments have limited success in activating the immune system.

Several studies have explored the potential synergy between EUS-RFA and immunotherapies, such as immune checkpoint inhibitors. The combination of RFA with immune modulation may help overcome resistance mechanisms in the tumor microenvironment and enhance the efficacy of systemic treatments[7,32]. However, these findings are still in the early stages, and further research is required to validate the clinical benefits of combining EUS-RFA with immunotherapies[7].

CONTROVERSIES

While EUS-RFA has shown promise in treating pancreatic cancer, several challenges and controversies remain. There is a need for large-scale randomized controlled trials to better define the long-term efficacy of EUS-RFA, especially in combination with other therapies such as chemotherapy and immunotherapy[1,2]. Standardization of procedural protocols and patient selection criteria remains insufficient, further contributing to uncertainty in clinical outcomes[1,12].

Another important controversy concerns the inconsistency of clinical outcomes across studies. While many reports show favorable results, others demonstrate neutral or limited benefits, particularly regarding survival outcomes and long-term disease control. These discrepancies may be related to heterogeneity in patient selection, tumor characteristics, RFA parameters, and operator experience[33]. Recognition of these neutral or less positive findings is essential to avoid overstating the efficacy of EUS-RFA and to highlight the areas where further validation is needed.

Moreover, procedural success and complication rates appear to be strongly influenced by operator expertise and institutional case volume. Centers with extensive experience in advanced endoscopic interventions tend to achieve higher technical success and lower adverse event rates, whereas outcomes in low-volume or less specialized centers may be more variable. This dependence on operator skill and institutional capacity significantly limits widespread adoption and complicates the development of universally applicable clinical guidelines.

CLINICAL GUIDELINES PERSPECTIVE

Current clinical guidelines from major professional societies continue to position EUS-RFA as an investigational or adjunctive modality rather than a standard therapeutic option. Both the American Society for Gastrointestinal Endoscopy and the European Association for the Study of the Liver note that although early clinical data are encouraging, the evidence remains insufficient to support routine incorporation of EUS-RFA into standard care pathways for pancreatic cancer.

Guidelines emphasize that the use of EUS-RFA should be limited to carefully selected patients and performed in high-experience centers with advanced endoscopic expertise, given the procedure’s dependence on operator skill, device familiarity, and institutional volume. Additionally, current recommendations highlight the need for further prospective trials to clarify optimal patient selection, procedural parameters, and long-term clinical outcomes before broader adoption can be recommended.

These guideline perspectives reinforce that EUS-RFA, while promising, remains an evolving technology whose role in pancreatic cancer management is still being defined within evidence-based frameworks.

FUTURE DIRECTIONS

In light of these controversies, several future research directions have emerged. There is a need for large-scale randomized controlled trials to better define the long-term efficacy of EUS-RFA, particularly when integrated into multimodal treatment strategies such as chemotherapy and immunotherapy.

In addition, the potential immunomodulatory effects of EUS-RFA open exciting avenues for future research. Studies investigating the combination of EUS-RFA with immune checkpoint inhibitors or other immune-modulating therapies may offer a new frontier in pancreatic cancer treatment[7,32]. This approach could significantly enhance the treatment landscape for pancreatic cancer, a disease that has historically been resistant to many therapeutic strategies.

Further technological refinement – including improvements in ablation probes, real-time temperature monitoring, and energy delivery modulation – may enhance both safety and efficacy. Expanding clinical evidence from high-volume centers and developing training frameworks may also help to decrease the variability in outcomes across institutions. Such advancements will be crucial for standardizing procedure protocols and expanding clinical adoption.

CONCLUSION

In conclusion, EUS-RFA represents a significant advancement in the treatment of pancreatic cancer, particularly for patients with unresectable or high-risk tumors. While it has shown excellent technical success rates and symptom relief, its long-term survival benefits remain uncertain. The integration of EUS-RFA with chemotherapy and immunotherapies may provide additional therapeutic advantages, and future research should focus on clarifying the role of EUS-RFA in multimodal treatment strategies. Larger randomized trials with long-term follow-up are essential to establish definitive guidelines and expand the clinical indications of EUS-RFA in pancreatic cancer management.