High operative risk of cool-tip radiofrequency ablation for unresectable pancreatic head cancer

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.

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.

Radiofrequency ablation for the management of pancreatic mass lesions

PURPOSE OF REVIEW

Patients with pancreatic tumors may have limited treatment options. Pancreatic tumor ablation is a novel and emerging treatment modality which can now be performed using endoscopic ultrasound (EUS) guidance. This modality is well suited to guide energy delivery for radiofrequency ablation (RFA) and microwave ablation. These approaches provide minimally invasive, nonsurgical methods for delivering energy to ablate pancreatic tumors in situ. This review summarizes the current data and safety profile for ablation in managing pancreatic cancer and pancreatic neuroendocrine tumors.

RECENT FINDINGS

RFA uses thermal energy to induce cell death by coagulative necrosis and protein denaturation. Studies have reported increased overall survival in patients with pancreatic tumors treated with EUS-guided RFA in a multimodality systemic approach and when used in palliative surgeries. Radiofrequency ablation may have corollary benefits in inducing an immune-modulatory effect. Tumor marker carbohydrate antigen 19-9 has been reported to decrease in response to RFA. Microwave ablation is an emerging modality.

SUMMARY

RFA utilizes focal thermal energy to induce cell death. RFA has been applied through open, laparoscopic, and radiographic modalities. EUS-guided approaches are now allowing RFA and microwave ablation to be performed for pancreatic tumors in situ.

Interventional Radiology in the Treatment of Pancreatic Adenocarcinoma: Present and Future Perspectives

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease; patients' long-term survival is strictly linked to the surgical resection of the tumor but only a minority of patients (2-3%) have a resectable disease at diagnosis. In patients with surgically unresectable disease, interventional radiology is taking on an increasing role in treatment with the application of loco-regional percutaneous therapies. The primary purposes of this narrative review are to analyze the safety and efficacy of ablative techniques in the management of borderline resectable and locally advanced diseases and to underline the role of the interventional radiologist in the management of patients with distant metastases. The secondary purpose is to focus on the synergy between immunotherapy and ablative therapies.

Endobiliary and Pancreatic Radiofrequency Ablations

Radio frequency ablation (RFA) involves use of thermal energy to perform ablation of tissues. It has a wide range of application in gastrointestinal tract. Over the last few years, several studies have reported successful and safe application in the biliary and pancreatic tissues. It is particularly beneficial in patients with biliary malignancies in whom it has shown to improve survival. Additionally, it can be applied in occluded metal stents secondary to tumor ingrowth to prolong the patency of stents. In pancreas, RFA can successfully ablate cystic lesions and neuroendocrine tumors. It has also been applied in unresectable pancreatic cancers. This review discusses the application of endobiliary and pancreatic RFAs.

Thermal ablation in pancreatic cancer: A scoping review of clinical studies

Background

Pancreatic cancer is a deadly cancer with a 5-year survival rate less than 10%. Only 20% of patients are eligible to receive surgery at diagnosis. Hence, new therapies are needed to improve outcomes for non-surgical candidates. Thermal ablation techniques can offer a non-invasive alternative to surgery.

Aim

The aim of this review is to map the literature for the use of thermal ablative techniques: Radiofrequency ablation (RFA), High-intensity focused ultrasound (HIFU), Microwave ablation (MWA), and Laser ablation (LA) in the management of patients with PC.

Methods

A search strategy was applied to PUBMED and EMBASE using keywords concerning pancreatic cancer, radiofrequency ablation, ultrasound ablation, laser ablation, and microwave ablation. The studies that fit this inclusion criteria were summarized in table format and results reviewed for interpretation.

Results

72 clinical studies were included. Most of the included studies related to RFA (n=35) and HIFU (n=27). The most common study design was retrospective (n=33). Only 3 randomized control trials (RCT) were included, all of which related to RFA. Safety outcomes were reported in 53 of the 72 studies, and survival outcomes were reported in 39. Statistically significant survival benefits were demonstrated in 11 studies.

Conclusion

The evidence for the benefit of MWA and LA in PC patients is limited. RFA and HIFU are safe and feasible therapies to be used in PC patients. Further RCTs where thermal techniques are standardized and reported are necessary in the future to elucidate thermal ablation’s clinical utility, and before an evidence-based decision on its routine use in PC management can be considered.

Nine-year survival of a 60-year-old woman with locally advanced pancreatic cancer under repeated open approach radiofrequency ablation: A case report

BACKGROUND

Radiofrequency ablation (RFA) is gaining popularity as an additional therapy for pancreatic ductal adenocarcinoma. RFA appears to be an attractive treatment option for patients with unresectable, locally advanced and nonmetastatic pancreatic cancer.

CASE SUMMARY

A 60-year-old woman with 2 mo intermittent upper abdominal pains was admitted to hospital. She had undergone radical gastrectomy (Billroth II) for gastric antral cancer. Contrast-enhanced computed tomography (CECT) and abdominal ultrasound displayed a primary tumor in the neck of the pancreas. Pathological examination showed that the lesion was a pancreatic ductal adenocarcinoma. According to the results of the imaging, open approach RFA was selected to treat the primary tumor. Eight months later, CECT follow-up revealed local recurrence of the tumor, and another open RFA was performed. Although there is evidence that RFA for recurrence of other cancers such as hepatocellular carcinoma may prolong patient survival, it remains unclear whether repeat RFA for local recurrence of pancreatic cancer is feasible. The patient continued to enjoy 9 years of life following the first RFA.

CONCLUSION

RFA of locally advanced, nonresectable, nonmetastatic, pancreatic tumor is characterized by feasibility-based treatment giving rise to tumor reduction based on improvement of quality of life.

US-Guided Percutaneous Radiofrequency Ablation of Locally Advanced Pancreatic Adenocarcinoma: A 5-Year High-Volume Center Experience

PURPOSE

 The aim of this study was to investigate the safety and effectiveness of percutaneous radiofrequency ablation (RFA) in locally advanced pancreatic cancer (LAPC) of the pancreatic body by assessing the overall survival of patients and evaluating the effects of the procedure in the clinical and radiological follow-up.

MATERIALS AND METHODS

 Patients with unresectable LAPC after failed chemoradiotherapy for at least six months were retrospectively included. Percutaneous RFA was performed after a preliminary ultrasound (US) feasibility evaluation. Contrast-enhanced computed tomography (CT) and CA 19.9 sampling were performed before and 24 hours and 30 days after the procedure to evaluate the effects of the ablation. Patients were followed-up after discharge considering the two main endpoints: procedure-related complications and death.

RESULTS

 35 patients were included, 5 were excluded. All patients underwent RFA with no procedure-related complications reported. The mean size of tumors was 49 mm before treatment. The mean dimension of the ablated necrotic zone was 32 mm, with a mean extension of 65 % compared to the whole tumor size. Tumor density was statistically reduced one day after the procedure (p < 0.001). The mean CA 19.9 levels before and 24 hours and 30 days after the procedure were 285.8 U/mL, 635.2 U/mL, and 336.0 U/mL, respectively, with a decrease or stability at the 30-day evaluation in 80 % of cases. The mean survival was 310 (65-718) days.

CONCLUSION

 Percutaneous RFA of LAPC is a feasible technique in patients who cannot undergo surgery, with great debulking effects and a very low complication rate.

Role of endoscopic ultrasound in anticancer therapy: Current evidence and future perspectives

The digestive system is one of the most common sites of malignancies in humans. Since gastrointestinal tumors represent a massive global health burden both in terms of morbidity and health care expenditures, scientists continuously develop novel diagnostic and therapeutic methods to ameliorate the detrimental effects of this group of diseases. Apart from the well-established role of the endoscopic ultrasound (EUS) in the diagnostic course of gastrointestinal and hepatobiliary malignancies, we have recently become acquainted with a vast array of its therapeutic possibilities. A multitude of previously established, evidence-based methods that might now be guided by the EUS emerged: Radiofrequency ablation, brachytherapy, fine needle injection, celiac plexus neurolysis, and endoscopic submucosal dissection. In this review we endeavored to provide a comprehensive overview of the role of these methods in different malignancies of the digestive system, primarily in the treatment and symptom control in pancreatic cancer, and additionally in the management of hepatic, gastrointestinal tumors, and pancreatic cysts.

Minimally invasive image-guided therapy of primary and metastatic pancreatic cancer

Pancreatic cancer is a challenging malignancy with limited treatment options and poor life expectancy. The only curative option is surgical resection, but only 15%-20% of patients are resectable at presentation because more than 50% of patients has distant metastasis at diagnosis and the rest of them has locally advanced pancreatic cancer (LAPC). The standard of care first line treatment for LAPC patients is chemotherapy with or without radiation therapy. Recent developments in minimally invasive ablative techniques may add to the treatment armamentarium of LAPC. There are increasing number of studies evaluating these novel ablative techniques, including radiofrequency ablation, microwave ablation, cryoablation and irreversible electroporation. Most studies which included pancreatic tumor ablation, demonstrated improved overall survival in LAPC patients. However, the exact protocols are yet to set up to which stage of the treatment algorithm ablative techniques can be added and in what kind of treatment combinations. Patients with metastatic pancreatic cancer has dismal prognosis with 5-year survival is only 3%. The most common metastatic site is the liver as 90% of pancreatic cancer patients develop liver metastasis. Chemotherapy is the primary treatment option for patients with metastatic pancreatic cancer. However, when the tumor is not responding to chemotherapy or severe drug toxicity develops, locoregional liver-directed therapies can provide an opportunity to control intrahepatic disease progression and improve survival in selected patients. During the last decade new therapeutic options arose with the advancement of minimally invasive technologies to treat pancreatic cancer patients. These new therapies have been a topic of increasing interest due to the severe prognostic implications of locally advanced and metastatic pancreatic cancer and the low comorbid risk of these procedures. This review summarizes new ablative options for patients with LAPC and percutaneous liver-directed therapies for patients with liver-dominant metastatic disease.

Role of radio-ablative technique for optimizing the survival of patients with locally advanced pancreatic adenocarcinoma (Review)

Pancreatic ductal adenocarcinoma (PDAC) is one of the most common and frequently diagnosed malignant tumor of the pancreas with few treatment options and poor life expectancy. Despite the advances in the surgical field, 40% of the patients are diagnosed with locally advanced disease which is not suitable for surgery. Radio-frequency ablation (RFA) has been described as a new ‘weapon’ in the multimodal treatment of PDAC, representing a cytoreductive procedure which must be completed with radiotherapy or chemo-radiotherapy. A systematic research was carried out utilizing the PubMed database in regards to this subject, to evaluate the role of RFA in PDAC management. Abstracts, letters-to-the-editor and non-English language manuscripts were excluded. The literature showed that RFA can be used in open and laparoscopic surgery but it is also feasible for endoscopic ultrasound (EUS-guided RFA) or percutaneous approach. Even though we found optimistic and encouraging reports on overall survival (OS), randomized studies are still required to corroborate these findings. Our review research underline that surgical resection remains the only radical treatment option, RFA being a safe and feasible technique reserved for unresectable, non-metastatic pancreatic tumors. Its combination with oncological treatment can improve the OS of these patients.

Role of Radiofrequency Ablation in the Management of Unresectable Pancreatic Cancer

Pancreatic cancer is one of the most aggressive malignancies of the digestive tract and carries a poor prognosis. The majority of patients have advanced disease at the time of diagnosis. Surgical resection offers the only curative treatment, but only a small proportion of patients can undergo surgical resection. Radiofrequency ablation (RFA) is a well-known modality in the management of solid organ tumors, however, its utility in the management of pancreatic cancer is under investigation. Since the past decade, there is increasing use of RFA as it provides a feasible palliation treatment in the management of unresectable pancreatic cancer. RFA causes tumor cytoreduction through multiple mechanisms such as coagulative necrosis, protein denaturation, and activation of anticancer immunity. The safety profile of RFA is controversial because of the high risk for complications, however, small prospective and retrospective studies have shown promising results in its applicability for palliative management of unresectable pancreatic malignancies. In this review, we discuss different approaches of RFA, their indications, technical accessibility, safety, and major complications in the management of unresectable pancreatic cancer.

Improving quality of life in pancreatic cancer patients following high-intensity focused ultrasound (HIFU) in two European centers

OBJECTIVES

Pancreatic cancer patients often have a high symptom burden, significantly impairing patients' quality of life (QOL). Nevertheless, there are hardly any reports on the impact of high-intensity focused ultrasound (HIFU) on the QOL of treated patients. For the first time, this study evaluated the effect of HIFU on QOL and compared these results in two European centers.

METHODS

Eighty patients with advanced pancreatic cancer underwent HIFU (50 in Germany, 30 in Bulgaria). Clinical assessment included evaluation of QOL and symptoms using the EORTC QLQ-C30 questionnaire at baseline and 1, 3, and 6 months after HIFU. Pain intensity was additionally evaluated with the numerical rating score (NRS).

RESULTS

Compared to baseline, global health significantly improved 3 and 6 months after HIFU treatment (p = 0.02). Functional subscales including physical, emotional, and social functioning were considerably improved at 6 months (p = 0.02, p = 0.01, and p = 0.01, respectively) as were leading symptom pain (p = 0.04 at 6 months), fatigue (p = 0.03 at 3 and p = 0.01 at 6 months), and appetite loss (p = 0.01 at 6 months). Moreover, pain intensity measured by NRS revealed effective and strong pain relief at all time points (p < 0.001). Reported effects were independent of tumor stage, metastatic status, and country of treatment.

CONCLUSIONS

This study showed that HIFU represents an effective treatment option of advanced pancreatic cancer improving QOL by increasing global health and mitigation of physical complaints with a low rate of side effects, independent of the examiner. Therefore, HIFU is a worthwhile additional treatment besides systemic palliative chemotherapy or best supportive care in management of this aggressive disease.

KEY POINTS

• In a prospective two-center study, it was shown that HIFU represents an effective treatment option of advanced pancreatic cancer improving QOL. • HIFU in pancreatic cancer patients is associated with a low rate of side effects, independent of the performer. • HIFU is a worthwhile additional treatment besides systemic palliative chemotherapy or best supportive care in management of this aggressive disease.

Endoscopic ultrasound-guided ethanol ablation for the management of a symptomatic pancreatic insulinoma

INTRODUCTION

pancreatic insulinoma is a sporadic, usually benign, frequently solitary tumor that is smaller than 20 mm. When it is functioning, patients present with symptoms of hypoglycemia secondary to insulin hypersecretion. The diagnosis is clinical, with biochemical and radiological confirmation. Surgery is the management of choice, although endoscopic ultrasound-guided ablation is currently being developed.

MATERIAL AND METHODS

we present a prospective case series of pancreatic insulinoma patients with symptoms of severe hypoglycemia, who were treated with endoscopic ultrasound-guided ethanol ablation as an alternative to surgical management.

RESULTS

technical and clinical success was achieved in all cases and there were no complications associated with the procedure.

CONCLUSION

the treatment of symptomatic insulinoma by endoscopic ultrasound-guided ethanol ablation could be a safe and effective alternative to surgical management in non-surgical patients or those who refuse surgery.

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.

Acute Phase Response and Postprocedural Evaluation of Open and Laparoscopic Cryoablation Procedures in Porcine Pancreases

OBJECTIVES

Cryoablation is a potentially less invasive locoregional ablation modality. Although cryoablation has been used to treat malignancy in various organs, a limited application of this modality in the pancreas has been reported.

METHODS

Acute phase response assessments and postprocedural course evaluations of 2 experimental locoregional ablation methods were conducted. In one method, open and laparoscopic cryoablation of a porcine pancreas using an argon-helium gas-based cryoablation system and monitoring of tissue temperature during the procedure were performed. In the other method, open cryoablation of a porcine pancreas using liquid nitrogen was performed. The animals were evaluated postoperatively.

RESULTS

The size of the cryolesion was larger in the second treatment than in the first. Laparoscopic cryoablation was associated with the formation of an iceball, which possibly affected the surrounding structures. The ablated region was adequately cooled with 10 minutes of freeze/repeat cycles. The area cooled to a temperature of less than -40°C was approximately half the size of the cryolesion in diameter. The swine used for the evaluation of the postprocedural course survived 3 weeks after the procedure with a temporal elevation of the serum lipase level.

CONCLUSIONS

Cryoablation of the pancreas was experimentally practicable without severe complications under direct or laparoscopic vision.

Endosonography-guided Radiofrequency Ablation in Pancreatic Diseases: Time to Fill the Gap Between Evidence and Enthusiasm

Over the past 20 years, endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) has generated interest as a novel minimally invasive tool in the multimodal treatment of pancreatic malignant and premalignant lesions. However, although optimization of probes and settings has made EUS-RFA relatively safe, questions on the ideal positioning of this treatment in a multimodal strategy remain unanswered. This review will summarize the technical aspects of EUS-RFA and available clinical experiences for each pancreatic indication (pancreatic cancer, neuroendocrine neoplasms, cystic lesions, and celiac ganglia neurolysis). Established indications will be discussed along those requiring additional clinical data or even proof-of-concept studies. A dedicated session will further discuss evidence expected to emerge from ongoing registered trials, together with issues that must be addressed in future research, including the possible combination with immunotherapy, and the personalization of this treatment on the basis of genetic profiling. Despite the great clinical enthusiasm and scientific fervor, while evidence-based answers are produced, EUS-RFA must be centralized in high-volume centers of recognized expertise, where multidisciplinary discussions of indications and actively recruiting research protocols are available.

Endoscopic Ultrasound-Guided Treatment of Pancreatic Cancer

PURPOSE OF REVIEW

The aim of this review is to evaluate the emerging role of endoscopic ultrasound (EUS) in the guidance of tumor-targeted therapies for patients with pancreatic cancer (PC).

RECENT FINDINGS

EUS-guided ablation, brachytherapy, fiducial marker placement, and antitumor agent injection have been described to date. EUS-guided fiducial placement for SBRT in pancreatic cancer has entered the clinical practice and is performed at many centers clinically without a research protocol. EUS-guided brachytherapy and RFA have been shown to be feasible and safe procedures, and potentially offer local disease control. Other potential techniques of EUS-guided treatment of pancreatic cancer are still considered experimental, with many of them appearing to be safe and reasonably well tolerated. However, their effectiveness and exact role in oncological treatment have yet to be established. Clinical trials with many of the techniques/agents described are underway and multicentric randomized trials with prospective design are eagerly awaited.

Endoscopic ultrasound in pancreatic cancer treatment: Facts and hopes

Pancreatic ductal adenocarcinoma is one of the most common causes of cancer-related deaths. Since most patients present with advanced disease, its prognosis is dismal. New and more effective therapeutic strategies are needed. Endoscopic ultrasound is currently an indispensable tool for the diagnosis and staging of pancreatic ductal adenocarcinoma. In recent years, endoscopic ultrasound has evolved to become also a therapeutic procedure. On one hand, the role of endoscopic ultrasound in the management of pancreatic cancer-related symptoms (pain, obstructive jaundice, and gastric outlet obstruction) is now well established. On the other hand, its use as a mean to the delivery of anti-tumor therapies (injecting anti-tumor agents, assisting in radiotherapy, and guiding ablative therapies) is still mostly experimental, despite growing evidence supporting its feasibility, safety and efficacy.

Safety of radiofrequency ablation in patients with locally advanced, unresectable pancreatic cancer: A phase II study

INTRODUCTION

Radiofrequency ablation (RFA) has been proposed as a new treatment option for locally advanced, unresectable pancreatic cancer (LAPC). In preparation of a randomized controlled trial (RCT), the aim of this phase II study was to assess the safety of RFA for patients with LAPC.

MATERIALS AND METHODS

Patients diagnosed with LAPC confirmed during surgical exploration between November 2012 and April 2014 were eligible for inclusion. RFA probes were placed under ultrasound guidance with a safety margin of at least 10 mm from the duodenum and 15 mm from the portomesenteric vessels. During RFA, the duodenum was continuously perfused with cold saline to reduce risk for thermal damage. Primary outcome was defined as the amount of major complications (Clavien-Dindo grade ≥III). RFA-related complications were predefined as: pancreatic fistula, pancreatitis, thermal damage to the portomesenteric vessels and duodenal perforation.

RESULTS

In total, 17 patients underwent RFA. Delayed gastric emptying (DGE) requiring endoscopic feeding tube placement occurred in 4 patients (24%) as only major complication. Five patients (29%) had a major complication other than DGE. One (6%) RFA-related major complications occurred. One patient (6%) died due to complications from a biliary leak following hepaticojejunostomy. After evaluation of the first 5 patients, gastrojejunostomy was no longer performed routinely. Since then severe DGE seemed to occur less (3/5 vs. 3/12 grade C DGE).

CONCLUSION

RFA is a major, but safe procedure for patients with LAPC if performed with strict predefined safety criteria. A RCT is currently investigating the true effectiveness of RFA in patients with LAPC.

Treatment of locally advanced pancreatic cancer with irreversible electroporation - a Danish single center study of safety and feasibility

OBJECTIVES

Irreversible electroporation (IRE) is a novel non-thermal ablative technique applied in the treatment of unresectable locally advanced pancreatic cancer (LAPC). This paper reports on the initial experience with IRE of unresectable LAPC in our institution.

METHODS

From October 2013 to March 2018, patients with unresectable LAPC referred for IRE at the Department of Gastrointestinal Surgery, Aalborg University Hospital, were considered for inclusion in the study. Ninety-day morbidity, 30-day mortality, pain score, length of hospital stay (LOS) and overall survival (OS) were recorded.

RESULTS

We included 33 patients receiving 40 IRE ablations in total. The median visual analogue scale (VAS)-score was four (range 0-10) two hours after IRE, and one (range 0-8) eight hours after IRE. The median LOS was one day (range 1-13 days). Post-procedural complications occurred in 21 of 40 ablations (53%), of which eight (20%) were major (Clavien-Dindo grade III or more). A proportion of the observed complications might be attributed to disease progression and not IRE per se. Although not statistically significant, we observed increased severity of complications in tumors above 3.5 cm. The 30-day mortality was 5% (2/40). The median OS was 10.7 months (range 0.6-53.8 months) from the initial IRE procedure, and 18.5 months (range 4.9-65.8 months) from time of diagnosis.

CONCLUSIONS

In our institution, IRE seems as a feasible consolidative treatment of unresectable LAPC with an acceptable safety profile. The oncological outcome of IRE in patients with unresectable LAPC is to be further evaluated in a planned phase 2 clinical trial (CHEMOFIRE-2).

EUS-guided pancreatic radiofrequency ablation: preclinical comparison of two currently available devices in a pig model

Introduction  Two devices are currently available to perform pancreatic radiofrequency ablation (P-RFA). Potential clinical indications might extend from the treatment of pancreatic cystic lesions to ablation of small pancreatic solid lesions or cytoreduction of advanced pancreatic adenocarcinomas, but more preclinical data from animal models are needed to optimize P-RFA operation. Methods  P-RFA was performed under laparotomy and under endoscopic ultrasonographic guidance on the liver and pancreatic parenchyma of four live swine using the Habib EUS RFA (EMcision Ltd, London, UK) probe and the EUS-RA needle (Taewoong Medical, Gyeonggi-do, South Korea). Animals were sacrificed 2 hours after the procedure. Influence of tuning ablation time and power on tissue ablation were studied by histopathological assessment of the maximal depth of tissue damage on representative slides for each P-RFA shot. Results  The Habib probe in the liver parenchyma resulted in tissue necrosis increasing within the range of 1.9 ± 0.5 mm (Power = 8 W, Time = 120 s) to 2.5 ± 1 mm (Power = 10 W, Time = 120 s). In the pancreatic parenchyma, tissue damage ranged from 3.1 ± 0.4 mm (Power = 8 W, Time = 120 s) to 2.3 ± 0.1 mm (12 W, 120 s) in depth. EUS RFA ablation of the liver parenchyma resulted in tissue damage ranging from 1.6 ± 0.2 mm (Power = 30 W, Time = 11 s) to 1.5 ± 0.1 mm (Power = 70 W, Time = 9 s); in the pancreas, ablation depth ranged from 3.6 ± 0.5 mm (Power = 30 W, Time = 15 s) to 3.8 ± 0.4 mm (Power = 70 W, Time = 11 s). Conclusion  Both devices allow for effective ablation of pancreatic tissue within 1.5 to 3.8 mm around the RFA electrode, with a modest influence of tuning power settings. Specific settings are recommended for each of the devices studied. Ablation of larger lesions may require more repeat P-RFA shots in different locations rather than a simple modulation of ablation parameters.

Ablative therapy in pancreatic cystic lesions

The growing incidence of cystic pancreatic tumours has become a major problem in daily clinical practice. These patients usually undergo follow-up programmes of questionable clinical efficacy that put significant strain on endoscopy units. Safe and effective alternatives to surgery are desperately needed in these cases. The aim of this study was to critically review the utility of ablative therapies in cystic pancreatic tumours.

Feasibility of EUS-guided Nd:YAG laser ablation of unresectable pancreatic adenocarcinoma

BACKGROUND AND AIMS

EUS has become an interventional technique in which a needle may be used as a vehicle to deliver therapeutic agents. Laser ablation (LA) has been used to treat many primary and secondary neoplasms. This study aimed to assess the feasibility of EUS-guided LA for unresectable (UR) pancreatic cancer.

METHODS

Patients with stage IIb-III pancreatic cancer underwent EUS-guided LA. All patients were unresponsive to previous chemoradiotherapy. LA was performed by using a 300-μm flexible fiber preloaded onto a 22-gauge fine needle. A 1064-nm wavelength neodymium-yttrium aluminum garnet (Nd:YAG) laser light with different power settings of 2 W for 800 J, 1000 J, and 1200 J; 3 W for 800 J, 1000 J, and 1200 J; and 4 W for 800 J, 1000 J, and 1200 J was used. Each patient was treated with a single application of 1 of these settings. The application time of the power settings ranged from 200 to 600 seconds.

RESULTS

Nine patients (median age, 74.7; range 55-85) underwent Nd:Yag LA. The mean size of the focal lesion was 35.4 mm (range, 21-45). The ablation area, demonstrated by 24-hour CT, ranged from .4 cm³ (for the lower power setting of 2 W/800 J) to a maximum of 6.4 cm³ (for 4 W/1000 J). The procedure was completed in all 9 patients without adverse events.

CONCLUSION

In our human experience, EUS-guided LA was feasible and well tolerated in patients with UR pancreatic cancer.

Percutaneous microwave thermosphere ablation of pancreatic tumours

Background

In oncologic field, thermo-ablative procedures have spread more and more. Percutaneous microwave ablation (MWA) showed same benefits and some advantages over radiofrequency ablation (RFA). To date, a disadvantage of both was the not totally predictable size and shape of ablation volume. The aim of this study was to assess feasibility and safety of MWA in nonresectable pancreatic head cancer using a new technology of MW with high power (100 W) and frequency of 2,450 MH.

Methods

Five patients with pancreatic head cancer treated with percutaneous MWA under ultrasound guidance were retrospectively reviewed. Mean lesion diameter was 27.8 mm (range, 25-32 mm). Follow-up was performed by CT after 1, 3, 6 and, when possible, 12 months. The shape of the ablation volume was evaluated with multiplanar reformatting (MPR) using roundness index (RI): a value near 1 represents a more spherical ablation zone shape, and a value distant from 1 implies an oval configuration. Ablation and procedure times were registered, together with hospital stay. The feasibility, safety and quality of life (QoL) were reported.

Results

The procedure was feasible in all patients (100%). A spherical shape of ablation zone was achieved in all cases (mean RI =0.97). Mean ablation and procedure time were respectively of 2.48 and 28 minutes. Mean hospital stay was 4 days. No major complications were observed. Minor complications resolved during the hospital stay. An improvement in QoL was observed in all patients despite a tendency to return to preoperative levels in the months following the procedure.

Conclusions

Percutaneous MWA is a feasible and safe approach for the palliative treatment of advanced stage tumors of the head of the pancreas, despite its complex anatomic relations. The spherical shape of the ablation volume could be related with an improving of the effectiveness and safety.

Irreversible electroporation of locally advanced solid pseudopapillary carcinoma of the pancreas: A case report

Introduction

Solid pseudopapillary Carcinoma (SPC) is a rare pancreatic Tumor with variable, usually low, malignancy potential. Howewer, several SPC are associated with aggressive behavior, local vascular infiltration, organ invasion, distant metastasis, and can be unresectable. Irreversible Electroporation (IRE) is an emerging non-thermal ablation technique for the treatment of locally advanced pancreatic carcinoma. We report the results of four year disease-free follow-up in a case of locally advanced unresectable SPC treated with IRE.

Presentation of case

A 24-year female patient with SPC of the pancreas underwent IRE during laparotomy under general anesthesia with intubation. Computed Tomography (CT) showed complete tumor thrombosis of splenic vein, encasement of celiac artery and mesenteric vein. Six insertions of 3–4 electrodes per insertion were performed. One month-CT-control showed shrinkage of the tumor. 6 months-post-treatment imaging showed complete regression of the mass, patent Splenic/mesenteric veins, absence of local recurrence or distant metastasis. Post treatment CTs at 12-18-24-30-36-42-48 months follow-up confirmed absence of local or distant recurrence.

Discussion

Surgery is the first choice curative treatment of SPC. Howewer aggressive surgery (duodeno-pancreasectomy) in unresectable cases, may have a high risk of recurrences, morbidities and death, and bring concerns about endocrine and exocrine insufficiency in a young patient. In these cases, IRE could be a safe and effective alternative treatment and could realize, in selected cases, the condition for a radical surgery, and a bridge to R-0 resection.

Conclusions

IRE could represent an effective alternative therapy to surgery in local advanced, unresectable SPC.

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Solid pseudopapillary Carcinoma (SPC) is a rare pancreatic Tumor with possible local vascular infiltration, distant metastasis, and can be unresectable.

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Irreversible Electroporation (IRE) is a non-thermal ablation technique for locally advanced pancreatic neoplasms.

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There is no case of SPC treated with IRE reported in the literature.

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IRE could be a safe and effective alternative treatment and could be a bridge to R-0 resection.

Interventional radiofrequency ablation: A promising therapeutic modality in the management of malignant biliary and pancreatic duct obstruction

Background: Malignant biliary and/or pancreatic obstruction has often encountered in the advanced stages of periampullary and cholangicarcinomas. Habib^TM Radiofrequency (RF) ablation has been successfully used in the management of various cancers of liver and pancreas. Percutaneous HPB probe (EMcision Ltd, London, UK) is a new addition to this class of tools. It is an endoluminal Radiofrequency (RF) catheter which works on the principle of ablation and induces coagulative necrosis to recanalize the obstructed duct. The aim of this study is to address the technical details of canalization, feasibilities and outcomes of percutaneous endo-luminal Radiofrequency (RF) catheter in patients with unresectable malignancy with obstructed bile and pancreatic duct (PD). Material and Method: A total of 134 patients with inoperable malignant obstruction of biliary and PD underwent RF based percutaneous endoluminal RF ablation in a tertiary referral centre between December 15^th, 2010 to August 7^th, 2015. This device was used in a sequential manner with an intent to recanalize the obstructed. Following the initial catheter drainage of the duct, subsequent percutaneous endobiliary RF ablation, the metallic stent was placed to recanalize the obstructed bile and PD secondary to unresectable malignancy under real-time fluoroscopic guidance. Results: The percutaneous RF based ablation of obstructed bile duct and PD with metallic stent placement was successfully achieved in 130 (97.01%) cases. The three failures were noted in cases of biliary obstruction whilst, one with PD obstruction. The patency restored in 124 and patients, where the procedure was successfully completed and revealed clinical improvement reported. Conclusion: The percutaneous endoluminal RF based ablation of obstructed duct with metallic stent placement appeared to be a safe, effective procedure and may improve survival in patients with advanced stage cancer presenting with biliary and PD obstruction. Considering the above mentioned evidence, this modality may stand ahead of stenting alone. This could be considered as viable modality in management of such patients where very limited treatment options are available.

Ablative Therapies for Locally Advanced Pancreatic Cancer

The vast majority of patients who present with pancreatic adenocarcinoma have locally advanced or metastatic disease at the time of presentation without possibility of cure. Although in recent years there have been some new promising chemotherapy regimens that improve overall survival by a few months, the prognosis remains dismal. There is, however, a subset of patients who experience durable stable disease or partial responses after initial courses of chemotherapy with locally advanced disease. In these select patients, there remains interest in local ablative therapy with or without resection as a means for local control, palliation of symptoms, and possible improved survival. This review describes the techniques, complications, and expected benefits of several ablative techniques as a treatment modality for locally advanced pancreatic cancer.

Irreversible electroporation for locally advanced pancreatic cancer through a minimally invasive surgery supported by laparoscopic ultrasound

INTRODUCTION

Pancreatic cancer is one of the most lethal cancers worldwide, with 5-years survival rate as low as 6%. The majority of pancreatic cancer patients present locally advanced or metastatic disease at diagnosis. Typically, patients affected by locally advanced pancreatic cancer (LAPC) do not undergo radical surgery but are treated with focal ablative therapies. However, a high rate of morbidity due to the heat sink effect has limited the application of ablative techniques on a routine basis in LAPC patients. Irreversible electroporation (IRE) has proved to be a new method of LAPC ablation.

PRESENTATION OF THE CASE

A 69-year-old woman affected by LAPC with good response to systemic chemotherapy with FOLFIRINOX and residual 35 mm mass in the neck of the pancreas underwent to IRE through a minimally invasive surgical approach under laparoscopic ultrasound guide. The post-operative course was uneventful and the patient was discharged after 5 days. Six months after surgery she had no evidence of distant or recurrent disease.

DISCUSSION

IRE has previously shown promising results in the treatment of LAPC, with relatively acceptable morbidity rates and improvement of survival. We report on the application of IRE through a minimally invasive surgical approach supported by laparoscopic ultrasound.

CONCLUSION

In conclusion, we propose a novel technical approach that combines the benefits of IRE on the treatment of patients affected by LAPC with the advantages of laparoscopic surgery.

Therapy of Pancreatic Neuroendocrine Tumors: Fine Needle Intervention including Ethanol and Radiofrequency Ablation

Pancreatic neuroendocrine tumors (PNETs) are increasingly being detected, though usually as incidental findings. Majority of the PNETs are non-functional and surgical resection is the standard of care for most of them. However, in patients with small PNETs localized within the pancreas, who are unfit or unwilling for surgery, alternate methods of treatment are needed. Direct methods of ablation of PNETs, using either ethanol injection or radiofrequency ablation (RFA), are emerging as effective methods. The limited literature available as case reports or case series on endoscopic ultrasound (EUS)-guided local ablation using either ethanol or RFA has demonstrated safety and efficacy along with short- to medium-term sustained relief. Long-term benefits with these local ablative therapies are awaited. Comparative studies are needed to show which of these two competing technologies is superior. Finally, comparative trials of EUS-guided ablation with surgical resection in terms of efficacy and safety will ensure their place in the management algorithm.

The role of irreversible electroporation (IRE) for locally advanced pancreatic cancer: a systematic review of safety and efficacy

OBJECTIVES

Irreversible electroporation (IRE) is a new modality for tumor ablation. Electrodes are placed around the tumor, and a pulsed, direct current with a field strength of 2000 V/cm is delivered. The direct current drives cells into apoptosis and cell death without causing significant heating of the tissues, which spares the extracellular matrix and proteins. The purpose of this review was to evaluate current experience of IRE for the ablation of pancreatic cancer.

MATERIAL AND METHODS

We searched PubMed for all studies of IRE in human pancreatic cancer in English reporting at least 10 patients.

RESULTS

The search yielded 10 studies, comprising a total of 446 patients. Percutaneous IRE was done in 142 patients, while 304 patients were treated during laparotomy. Tumor sizes ranged from median 2.8 to 4.5 cm. Post-procedural complications occurred in 35% of patients, most of them were less severe. Nine patients (2.0%) died after the procedure. The technical success rate was 85-100%. The median recurrence-free survival was 2.7-12.4 months after IRE treatment. The median overall survival was 7-23 months postoperatively. The longest overall survival was noted when IRE was used in conjunction with pancreatic resection.

CONCLUSIONS

IRE seems feasible and safe with a low post-procedural mortality. Further efforts are needed to address patient selection and efficacy of IRE, as well as the use of IRE for 'margin accentuation' during surgical resection.

The Emerging Role of Endoscopists in Treating Unresectable Pancreatic Cancer

Pancreatic adenocarcinoma is the eighth leading cause of cancer deaths worldwide in men and ninth leading cause in women. Surgical resection offers the only chance of potential cure; however, only 9.4% of patients present at the localized, resectable stage, whereas the rest present at the locally advanced or metastatic, unresectable stages. Because of the guarded outcomes following systemic chemoradiation and the associated systemic toxicities, locoregional therapies have recently gained popularity. Various endoscopic techniques (endoscopic ultrasound [EUS]-guided ablative therapies, fine-needle instillation of antitumor agents, stereotactic body radiation therapy with EUS-guided fiducial marker placement, and EUS-guided brachytherapy) have been explored over the past several years. Endoscopic therapy plays a role in the treatment of unresectable pancreatic adenocarcinoma. Its minimal invasiveness and increased precision of delivering oncologic treatments under EUS guidance render it as a favorable option for patients who do not benefit from surgical resection. New endoscopic therapies are currently under investigation, and the emerging role of the endoscopist in the treatment of unresectable pancreatic cancer continues to grow.

Endoscopic ultrasound-guided radiofrequency ablation in gastroenterology: New horizons in search

Radiofrequency ablation (RFA) has been widely used for the treatment of various solid organ malignancies. Over the last decade, endosonographers have gradually shifted the application of RFA from porcine models to humans to treat a spectrum of diseases. RFA is performed in patients with pancreatic carcinoma who are not candidates for surgery. In this paper, we will discuss various indications for RFA, its procedural details and complications. At present, endoscopic ultrasound-guided RFA is gradually incorporated into the management of various diseases and opens a new avenue for disease treatment.

Percutaneous Radiofrequency Ablation of Unresectable Locally Advanced Pancreatic Cancer: Preliminary Results

AIM

The objective of this study was to evaluate the efficacy of percutaneous radiofrequency ablation of locally advanced pancreatic cancer located in the pancreatic body.

MATERIALS AND METHODS

Patients with biopsy-proven locally advanced pancreatic adenocarcinoma were considered for percutaneous radiofrequency ablation. Postprocedural computed tomography studies and Ca19.9 tumor marker evaluation were performed at 24 hours and 1 month. At computed tomography, treatment effect was evaluated by excluding the presence of complications. The technical success of the procedure is defined at computed tomography as the achievement of tumoral ablated area.

RESULTS

Twenty-three patients have been included in the study. Five of the 23 patients were excluded. At computed tomography, the mean size of the intralesional postablation necrotic area was 32 mm (range: 15-65 mm). Technical success of the procedure has been obtained in 16 (93%) of the 18 cases. None of the patients developed postprocedural complications. Mean Ca19.9 serum levels 1 day before, 1 day after, and 1 month after the procedure were 285.8 U/mL (range: 16.6-942.0 U/mL), 635.2 U/mL (range: 17.9-3368.0 U/mL), and 336.0 U/mL (range: 7.0-1400.0 U/mL), respectively. Follow-up duration was less than 6 months for 11 patients and more than 6 months for 7 patients. At the time of the draft of this article, the mean survival of the patients included in the study was 185 days (range: 62-398 days).

CONCLUSION

Percutaneous radiofrequency ablation of locally advanced adenocarcinoma has a high technical success rate and is effective in cytoreduction both at imaging and laboratory controls.

Theoretical investigation of transgastric and intraductal approaches for ultrasound-based thermal therapy of the pancreas

Background

The goal of this study was to theoretically investigate the feasibility of intraductal and transgastric approaches to ultrasound-based thermal therapy of pancreatic tumors, and to evaluate possible treatment strategies.

Methods

This study considered ultrasound applicators with 1.2 mm outer diameter tubular transducers, which are inserted into the tissue to be treated by an endoscopic approach, either via insertion through the gastric wall (transgastric) or within the pancreatic duct lumen (intraductal). 8 patient-specific, 3D, transient, biothermal and acoustic finite element models were generated to model hyperthermia (n = 2) and ablation (n = 6), using sectored (210°–270°, n = 4) and 360° (n = 4) transducers for treatment of 3.3–17.0 cm³ tumors in the head (n = 5), body (n = 2), and tail (n = 1) of the pancreas. A parametric study was performed to determine appropriate treatment parameters as a function of tissue attenuation, blood perfusion rates, and distance to sensitive anatomy.

Results

Parametric studies indicated that pancreatic tumors up to 2.5 or 2.7 cm diameter can be ablated within 10 min with the transgastric and intraductal approaches, respectively. Patient-specific simulations demonstrated that 67.1–83.3% of the volumes of four sample 3.3–11.4 cm³ tumors could be ablated within 3–10 min using transgastric or intraductal approaches. 55.3–60.0% of the volume of a large 17.0 cm³ tumor could be ablated using multiple applicator positions within 20–30 min with either transgastric or intraductal approaches. 89.9–94.7% of the volume of two 4.4–11.4 cm³ tumors could be treated with intraductal hyperthermia. Sectored applicators are effective in directing acoustic output away from and preserving sensitive structures. When acoustic energy is directed towards sensitive structures, applicators should be placed at least 13.9–14.8 mm from major vessels like the aorta, 9.4–12.0 mm from other vessels, depending on the vessel size and flow rate, and 14 mm from the duodenum.

Conclusions

This study demonstrated the feasibility of generating shaped or conformal ablative or hyperthermic temperature distributions within pancreatic tumors using transgastric or intraductal ultrasound.

Endoscopic ultrasonography-guided tumor ablation

Real-time guidance of needle advancement has transformed endoscopic ultrasound (EUS) from a diagnostic to an interventional procedure. EUS-guided fine-needle puncture has application in various interventional procedures (drainage of pseudocyst, biliary intervention, and injection of drugs). Celiac plexus or ganglion neurolysis for pain control is the major current EUS-guided fine-needle injection procedure. Feasibility and safety to accurately position needle devices and/or inject under real-time EUS imaging with precise delivery of interventional agent have expanded the use of EUS to ablate tumors. These include radiofrequency ablation, or delivery of fiducial markers, potential antitumor agents, or radioactive seeds, in the cancer mass. Minimally invasive EUS-guided antitumor therapy is primarily used for pancreatic cancer because of better anatomic access (vs other imaging modality) and the dismal prognosis (despite improvements in surgery and chemoradiation). Also, the response to parenteral chemotherapy in pancreatic cancer is poor because of suboptimal drug delivery resulting from hypovascularity and abundant desmoplasia. Other targets for EUS-guided tumor ablation are pancreatic neuroendocrine tumor and pancreatic cyst lesion, which are less aggressive and curable by resection. However, patients non-eligible for surgery may benefit from local EUS-guided ablation.

Endoscopic Radiofrequency Ablation of the Pancreas

Radiofrequency ablation (RFA) is a well-established technique to ablate dysplastic and neoplastic tissue via local thermal coagulative necrosis. Despite the widespread use in management of several cancers, the application of RFA in pancreas has been limited due to the increased risks of complications from the increased sensitivity of pancreatic tissue to thermal injury and proximity to vascular and biliary structures. RFA has been successfully used during laparotomy for locally advanced pancreatic carcinoma but requires an invasive approach. Endoscopic ultrasound-guided RFA offers the best combination of excellent visualization, real-time imaging guidance, and precise localization with minimal invasiveness. Several animal and human studies have demonstrated the technical feasibility and safety of endoscopic RFA in the pancreas. This article provides a comprehensive review of endoscopic RFA in the management of pancreatic lesions.

Irreversible Electroporation of the Pancreas Using Parallel Plate Electrodes in a Porcine Model: A Feasibility Study

BACKGROUND

Irreversible electroporation (IRE) with needle electrodes is being explored as treatment option in locally advanced pancreatic cancer. Several studies have shown promising results with IRE needles, positioned around the tumor to achieve tumor ablation. Disadvantages are the technical difficulties for needle placement, the time needed to achieve tumor ablation, the risk of needle track seeding and most important the possible occurrence of postoperative pancreatic fistula via the needle tracks. The aim of this experimental study was to evaluate the feasibility of a new IRE-technique using two parallel plate electrodes, in a porcine model.

METHODS

Twelve healthy pigs underwent laparotomy. The pancreas was mobilized to enable positioning of the paddles. A standard monophasic external cardiac defibrillator was used to perform an ablation in 3 separate parts of the pancreas; either a single application of 50 or 100J or a serial application of 4x50J. After 6 hours, pancreatectomy was performed for histology and pigs were terminated.

RESULTS

Histology showed necrosis of pancreatic parenchyma with neutrophil influx in 5/12, 11/12 and 12/12 of the ablated areas at 50, 100, and 4x50J respectively. The electric current density threshold to achieve necrosis was 4.3, 5.1 and 3.4 A/cm2 respectively. The ablation threshold was significantly lower for the serial compared to the single applications (p = 0.003). The content of the ablated areas differed between the applications: areas treated with a single application of 50 J often contained vital areas without obvious necrosis, whereas half of the sections treated with 100 J showed small islands of normal looking cells surrounded by necrosis, while all sections receiving 4x 50 J showed a homogeneous necrotic lesion.

CONCLUSION

Pancreatic tissue can be successfully ablated using two parallel paddles around the tissue. A serial application of 4x50J was most effective in creating a homogeneous necrotic lesion.

Thermal ablation of pancreatic cyst with a prototype endoscopic ultrasound capable radiofrequency needle device: A pilot feasibility study

BACKGROUND AND OBJECTIVES

Pancreatic cysts are evaluated by endoscopic ultrasound and fine needle aspiration (EUS). The only accepted treatment is pancreatectomy, which is associated with morbidity and mortality. This study evaluated the optimal thermal dosimetry of a novel radiofrequency ablation device using a standard electrosurgical unit in ex vivo cyst models.

METHODS

A modified EUS 22-gauge monopolar needle prototype with a tip electrode connected to a standard electrosurgical unit (Erbe USA, Marietta, GA, USA) was used to induce a subboiling point temperature. A cyst model was created using 2-cm sections of porcine small intestine ligated and filled with saline. After ablation, the cyst models were prepared for pathological evaluation. The epithelial layers were measured in at least two different sites with a micrometer and compared with the corresponding control sample.

RESULTS

Thirty-two cyst models were ablated with maximum temperatures of 50°C, 60°C, 90°C, and 97°C in 8, 11, 11, and 2 cysts, respectively. Longer ablation times were required to induce higher temperatures. A trend in the reduction in thickness of the measured layers was observed after exposure to higher temperatures. A temperature over 50°C was required for the ablation of the muscularis, submucosa, and villi, and over 60°C was required to ablate the mucosal crypts.

CONCLUSIONS

In a preclinical model, a novel radiofrequency EUS-capable needle connected to a standard electrosurgical unit using standard low-voltage coagulation provided ablation in a temperature-dependent fashion with a threshold of at least 60°C and a safe cyst margin below 97°C. This potentially will allow low-cost, convenient cyst ablation.

Percutaneous ablation of pancreatic cancer

Pancreatic ductal adenocarcinoma is a highly aggressive tumor with an overall 5-year survival rate of less than 5%. Prognosis and treatment depend on whether the tumor is resectable or not, which mostly depends on how quickly the diagnosis is made. Chemotherapy and radiotherapy can be both used in cases of non-resectable pancreatic cancer. In cases of pancreatic neoplasm that is locally advanced, non-resectable, but non-metastatic, it is possible to apply percutaneous treatments that are able to induce tumor cytoreduction. The aim of this article will be to describe the multiple currently available treatment techniques (radiofrequency ablation, microwave ablation, cryoablation, and irreversible electroporation), their results, and their possible complications, with the aid of a literature review.

Synergetic effects of silver and gold nanoparticles in the presence of radiofrequency radiation on human kidney cells

OBJECTIVE

The aim of this study was to compare the effects of radiofrequency radiation (RF) in synergism with gold (Au) and silver (Ag) nanoparticles (NPs) on the survival fraction of human normal kidney (HNK) and human embryonic kidney (HEK) cells.

MATERIALS AND METHODS

HNK and HEK cells were divided into three groups as control, 1 and 2 h/day-irradiated groups for 8 days. To compare the effects of RF in the presence of Au-NPs and Ag-NPs, the cells were incubated with NPs during the irradiation. In other words, six other groups were designed for the cell incubated with Au-NPs and Ag-NPs including control, 1 and 2 h/day-irradiated groups for 8 days. Generalized estimating equation model was applied to consider the natural correlation of repeated measurements over the time.

RESULTS

The mean survival fractions of HNK + Ag-NPs and HEK + Au-NPs were 0.098 less, 0.184 and 0.055 more than HEK cells, respectively. Along with the time, the mean fraction in HEK + Ag-NPs and HEK + Au-NPs groups in comparison with the HEK increased by the rate of 0.005 and decreased by the rates of 0.01 and 0.005, respectively. The mean survival fractions in HEK + Ag-NPs and HEK + Au-NPs were significantly less than that of HEK cells (P < 0.05).

CONCLUSIONS

RF radiation can affect both HNK and HEK cells when irradiated for 2 h/day for 8 days. The results showed that the Ag-NPs do not increase the synergistic effects of RF compared to the Au-NPs. RF radiation at the presence of Au-NPs can be used as an efficient treatment for melanoma.

Temperature responsive porous silicon nanoparticles for cancer therapy - spatiotemporal triggering through infrared and radiofrequency electromagnetic heating

One critical functionality of the carrier system utilized in targeted drug delivery is its ability to trigger the release of the therapeutic cargo once the carrier has reached its target. External triggering is an alluring approach as it can be applied in a precise spatiotemporal manner. In the present study, we achieved external triggering through the porous silicon (PSi) nanoparticles (NPs) by providing a pulse of infrared or radiofrequency radiation. The NPs were grafted with a temperature responsive polymer whose critical temperature was tailored to be slightly above 37°C. The polymer coating improved the biocompatibility of the NPs significantly in comparison with their uncoated counterparts. Radiation induced a rapid temperature rise, which resulted in the collapse of the polymer chains facilitating the cargo release. Both infrared and radiofrequency radiation were able to efficiently trigger the release of the encapsulated drug in vitro and induce significant cell death in comparison to the control groups. Radiofrequency radiation was found to be more efficient in vitro, and the treatment efficacy was verified in vivo in a lung carcinoma (3LL) mice model. After a single intratumoral administration of the carrier system combined with radiofrequency radiation, there was clear suppression of the growth of the carcinoma and a prolongation of the survival time of the animals.

TOC IMAGE

The temperature responsive (TR) polymer grafted on the surface of porous silicon nanoparticles (PSi NPs) changes its conformation in response to the heating induced by infrared or radiofrequency radiation. The conformation change allows the loaded doxorubicin to escape from the pores, achieving controlled drug release from TR PSi NPs, which displayed efficacy against malignant cells both in vitro and in vivo.

Ablation Strategies for Locally Advanced Pancreatic Cancer

With the advent of novel and somewhat effective chemotherapy against pancreas cancer, several groups developed a new interest on locally advanced pancreatic cancer (LAPC). Unresectable tumors constitute up to 80% of pancreatic cancer (PC) at the time of diagnosis and are associated with a 5-year overall survival of less than 5%. To control those tumors locally, with perhaps improved patients survival, significant advances were made over the last 2 decades in the development of ablation methods including cryoablation, radiofrequency ablation, microwave ablation, high intensity focused ultrasound and irreversible electroporation (IRE). Many suggested a call for caution for possible severe or lethal complications in using such techniques on the pancreas. Most fears were on the heating or freezing of the pancreas, while non-thermal ablation (IRE) could offer safer approaches. The multimodal therapies along with high-resolution imaging guidance have created some enthusiasm toward ablation for LAPC. The impact of ablation techniques on primarily non-resectable PC remains, however, unclear.

Variation of tumoral marker after radiofrequency ablation of pancreatic adenocarcinoma

BACKGROUND

To evaluate the correlation between variations of CA 19.9 blood levels and the entity of necrosis at CT after radiofrequency ablation (RFA) of unresectable pancreatic adenocarcinoma.

METHODS

In this study, from June 2010 to February 2014, patients with diagnosis of unresectable and not metastatic pancreatic ductal adenocarcinoma, expressing tumor marker CA 19.9, treated with RFA procedure were included. All these patients underwent RFA. CT study was performed 1 week after RFA. The dosage of CA 19.9 levels was performed 1 month after RFA. Features of necrosis at CT, as mean entity, density and necrosis percentages compared to the original lesion, were evaluated and compared by using t-test with CA 19.9 blood levels variations after RFA procedure.

RESULTS

In this study were included 51 patients with diagnosis of unresectable and not metastatic pancreatic ductal adenocarcinoma, expressing tumor marker CA 19.9, treated with RFA procedure and with CT study and CA 19.9 available for analysis. After the procedure, CA 19.9 blood levels reduced in 24/51 (47%), remained stable in 10/51 (20%) and increased in 17/51 (33%). In patients with CA 19.9 levels reduced, the tumor marker were reduced less than 20% in 4/24 (17%) and more than 20% in 20/24 (83%); instead the tumor marker were reduced less than 30% in 8/24 (33%) and more than 30% in 16/24 (67%). At CT scan necrotic area density difference was not statistically significant. Also there was no statistically significant difference among the mean area, the mean volume and the mean ablation volume in percentage related to the treated tumor among the three different groups of patients divided depending on the CA 19.9 blood levels. But a tendency to a statistically significant difference was found in comparing the mean percentage of ablation volume between two subgroups of patients with a decrease of CA 19.9 levels with less or more than 20% reduction of tumor markers and between two subgroups with less or more than 30% reduction of CA 19.9 levels.

CONCLUSIONS

RFA of unresectable pancreatic adenocarcinoma induces reduction of CA 19.9 blood levels in about half of the cases.

Local Ablative Strategies for Ductal Pancreatic Cancer (Radiofrequency Ablation, Irreversible Electroporation): A Review

Pancreatic ductal adenocarcinoma (PDAC) has still a dismal prognosis. Locally advanced pancreatic cancer (LAPC) accounts for the 40% of the new diagnoses. Current treatment options are based on chemo- and radiotherapy regimens. Local ablative techniques seem to be the future therapeutic option for stage-III patients with PDAC. Radiofrequency Ablation (RFA) and Irreversible Electroporation (IRE) are actually the most emerging local ablative techniques used on LAPC. Initial clinical studies on the use of these techniques have already demonstrated encouraging results in terms of safety and feasibility. Unfortunately, few studies on their efficacy are currently available. Even though some reports on the overall survival are encouraging, randomized studies are still required to corroborate these findings. This study provides an up-to-date overview and a thematic summary of the current available evidence on the application of RFA and IRE on PDAC, together with a comparison of the two procedures.

Initial experience of EUS-guided radiofrequency ablation of unresectable pancreatic cancer

BACKGROUND AND AIMS

Radiofrequency ablation (RFA) has been used as a valuable treatment modality for various unresectable malignancies. EUS-guided radiofrequency ablation (EUS-RFA) of the porcine pancreas was reported to be feasible and safe in our previous study, suggesting that EUS-RFA may be applicable as an adjunct and effective alternative treatment method for unresectable pancreatic cancer. This study aimed to assess the technical feasibility and safety of EUS-RFA for unresectable pancreatic cancer.

METHODS

An 18-gauge endoscopic RFA electrode and a radiofrequency generator were used for the procedure. The length of the exposed tip of the RFA electrode was 10 mm. After insertion of the RFA electrode into the mass, the radiofrequency generator was activated to deliver 20 to 50 W ablation power for 10 seconds. Depending on tumor size, the procedure was repeated to sufficiently cover the tumor.

RESULTS

EUS-RFA was performed successfully in all 6 patients (median age 62 years, range 43-73 years). Pancreatic cancer was located in the head (n = 4) or body (n = 2) of the pancreas. The median diameter of masses was 3.8 cm (range 3cm-9cm). Four patients had stage 3 disease, and 2 patients had stage 4 disease. After the procedure, 2 patients experienced mild abdominal pain, but there were no other adverse events such as pancreatitis or bleeding.

CONCLUSIONS

EUS-RFA could be a technically feasible and safe option for patients with unresectable pancreatic cancer.

EUS-guided radiofrequency ablation for management of pancreatic insulinoma by using a novel needle electrode (with videos)

BACKGROUND AND AIMS

Insulinomas are one of the most common functional pancreatic neuroendocrine tumors. Surgical removal is the standard of care. Patients unfit for or refusing surgery need an alternative nonsurgical method to alleviate symptoms. EUS has been used to localize, aspirate, and tattoo insulinomas and to inject alcohol for local ablation. This study is aimed at assessing the feasibility of EUS-guided radiofrequency ablation (EUS-RFA) for managing patients with a symptomatic insulinoma by using a novel EUS-RFA needle electrode.

METHODS

The EUS-RFA system used consists of a prototype 19-gauge needle electrode, generator, and internal cooling system. EUS-guided RFA is performed under real-time visualization at 50 W to ablate pancreatic insulinomas.

RESULTS

In this observational human case series from a tertiary care center, 3 patients with a symptomatic pancreatic insulinoma, not eligible for surgery, underwent EUS-RFA by using an internally cooled prototype needle electrode. All had rapid symptom relief with biochemical improvement and remained symptom free at 11 to 12 months of follow-up. There were no procedure-related adverse events.

CONCLUSIONS

EUS-RFA with the novel device can be considered in select patients with a symptomatic pancreatic insulinoma based on preliminary findings of a beneficial effect without adverse events. Assessment of the safety profile requires larger prospective trials.

Endoscopic ultrasound-fine needle injection for oncological therapy

The minimal invasiveness and precision of endoscopic ultrasound (EUS) has lead to both its widespread use as a diagnostic and staging modality for gastrointestinal and pancreaticobiliary malignancies, and to its expanding role as a therapeutic modality. EUS-guided celiac plexus neurolysis is now a well-accepted modality for palliation of pain in patients with pancreatic cancer. EUS-guided ablation, brachytherapy, fiducial marker placement, and antitumor agent injection have been described as methods of performing minimally invasive oncological therapy. EUS-fine needle injection may be performed as adjunctive, alternative, or palliative treatment. This review summarizes the studies to date that have described these methods. A literature search using the PubMed/MEDLINE databases was performed. While most published studies to date are limited with disappointing outcomes, the concept of a role of EUS in oncological therapy seems promising.