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

Endoscopy-guided ablation of pancreatic lesions: Technical possibilities and clinical outlook

Endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP)-guided ablation procedures are emerging as a minimally invasive therapeutic alternative to radiological and surgical treatments for locally advanced pancreatic cancer (LAPC), pancreatic neuroendocrine tumours (PNETs), and pancreatic cystic lesions (PCLs). The advantages of treatment under endoscopic control are the real-time imaging guidance and the possibility to reach a deep target like the pancreas. Currently, radiofrequency probes specifically designed for ERCP or EUS ablation are available as well as hybrid cryotherm probe combining radiofrequency with cryotechnology. To date, many reports and case series have confirmed the safety and feasibility of that kind of ablation technique in the pancreatic setting. Moreover, EUS-guided fine-needle injection is emerging as a method to deliver ablative and anti-tumoral agents inside the tumuor. Ethanol injection has been proposed mostly for the treatment of PCLs and for symptomatic functioning PNETs, and the use of gemcitabine and paclitaxel is also interesting in this setting. EUS-guided injection of chemical or biological agents including mixed lymphocyte culture, oncolytic viruses, and immature dendritic cells has been investigated for the treatment of LAPC. Data on the long-term efficacy of these approaches, and large prospective randomized studies are needed to confirm the real clinical benefits of these techniques for the management of pancreatic lesions.

EUS for pancreatic cystic neoplasms: The roadmap to the future is much more than just a few shades of gray

Pancreatic cystic and neoplasms are being diagnosed with increasing frequency. Accurate diagnosis and determination of benign versus malignant lesions is crucial for determining need for surveillance versus surgery or endoscopic therapy as well as avoiding unnecessary surgery in cysts with no malignant potential. Tumor markers such as KRAS and GNAS hold promise, but which molecular marker or a combination of markers is most useful and cost effective remains to be seen. Advanced imaging with confocal laser endomicroscopy can serve as an optical biopsy and play a part in the diagnostic algorithm. Microforceps aided biopsy of pancreatic cyst wall and tumor contents hold great promise as they allow direct tissue acquisition. Much progress has been made in the role of EUS guided evaluation of pancreatic cystic neoplasms over the last several years, and with the advances enumerated above, the future is more than just a few shades of gray. Future studies should include prospective multi-arm trials of microforceps biopsy versus conventional EUS-FNA and use of biochemical and molecular markers, confocal laser endomicroscopy or a combination thereof to determine best approach to pancreatic cystic neoplasms. In Osler's words, 'Medicine is a science of uncertainty and an art of probability'. Incorporation of advanced imaging and molecular markers into a new diagnostic algorithm with subsequent validation through retrospective and prospective studies has the potential to increase diagnostic accuracy and guide optimal management of patients and improve outcomes.

Review of endoscopic radiofrequency in biliopancreatic tumours with emphasis on clinical benefits, controversies and safety

Most pancreatic cancers and extrahepatic cholangiocarcinomas are unresectable at the time of diagnosis, and even in case of a resectable cancer, for elderly or patients with coexistent comorbidities, surgery is not an option. Current treatment alternatives in these scenarios are very limited. Biliary stenting with self-expanding metal stents (SEMS) is the mainstay palliative treatment of biliary obstruction due to unresectable pancreatic cancer or cholangiocarcinoma. Nevertheless, more than 50% of SEMS become occluded after 6 mo due to tumour over- and ingrowth, leading to hospital readmissions and reinterventions that significantly impair quality of life. Regimes of chemotherapy or chemoradiotherapy also provide minimal survival benefits. Therefore, novel therapies are eagerly awaited. Radiofrequency (RF) energy causes coagulative necrosis leading to local destruction of the accessed malignant tissue and has an established role in the treatment of malignancies in several solid organs, especially liver cancers. However, pancreatic and extrahepatic biliary cancers are not easily accessed by a percutaneous route, making the procedure dangerous. Over the past five years, the development of dedicated devices compatible with endoscopic instruments has offered a minimally invasive option for RF energy delivery in biliopancreatic cancers. Emerging experience with endoscopic RF ablation (RFA) in this setting has been reported in the literature, but little is known about its feasibility, efficacy and safety. A literature review makes it clear that RFA in biliopancreatic tumours is feasible with high rates of technical success and acceptable safety profile. Although available data suggest a benefit of survival with RFA, there is not enough evidence to draw a firm conclusion about its efficacy. For this reason, prospective randomized trials comparing RFA with standard palliative treatments with quality-of-life and survival endpoints are required. Anecdotal reports have also highlighted a potential curative role of RFA in small pancreatic tumours and benign conditions, such as ductal extension of ampullomas, intrahepatic adenomas or non-tumoural biliary strictures. These newest indications also deserve further examination in larger series of studies.

Interventional Therapy for Pancreatic Cancer

BACKGROUND

Palliative therapy and primarily chemoradiotherapy are the mainstream treatments in patients with locally advanced or metastatic pancreatic cancer (PC). Conventional endoscopy and endoscopic ultrasound (EUS)-guided interventional therapy has emerged as an important procedure for PC management. In this review, the progress in conventional endoscopy and EUS for PC management is discussed.

SUMMARY

For local palliative therapy against PC, EUS-guided fine needle injection (FNI) could deliver different kinds of agents, such as radioactive seeds and fiducials. Although their feasibility and safety have been proven, the long-term efficiency of EUS-FNI is still not established. For pain, EUS-celiac plexus neurolysis (CPN) is effective. However, CPN can only relieve the pain to a limited degree, with short duration. Endoscopy-guided stent placement is the preferred strategy for biliary and duodenal obstruction. Plastic and metal stents are equally effective for the relief of obstructive jaundice. The functional times of metal stents are longer than those of a plastic stent.

KEY MESSAGE

For biliary obstruction, a metal stent is the first choice. The long-term efficiency of EUS-FNI still needs further study.

PRACTICAL IMPLICATIONS

Endoscopy and EUS-guided interventions have gradually become the mainstream method for local treatment of PC due to mini-invasiveness and real-time observation. PC is the second most common gastrointestinal malignancy and the sixth leading cause of cancer mortality in the United States, leading to about 4.0% of all cancer deaths [Siegel et al: CA Cancer J Clin 2014;64:9-29]. The only curative approach for patients with PC is surgical resection, but unfortunately 80-90% of patients have a surgically inoperable disease, with 53% having local metastases at the time of diagnosis [Weinberg et al: Oncology (Williston Park) 2015;29:809-820, 886]. Therefore, palliative therapy and primarily chemoradiotherapy are the mainstream of treatment in patients with locally advanced or metastatic PC. Although overall survival has improved from 6 to 8.5-11 months (some of them even survived for a year or more), the overall survival rate has not improved, and the 5-year survival is less than 4% [Weinberg et al: Oncology (Williston Park) 2015;29:809-820, 886; Greenlee et al: CA Cancer J Clin 2001;51:15-36; Zhang et al: Gastroenterol Res Pract 2016;2016:8962321]. Hence, it is crucial to develop more effective local treatment strategies for tumor tissue and symptom palliation. At present, endoscopy has gradually become the mainstream method for local treatment of gastrointestinal cancer due to mini-invasiveness and real-time observation. Conventional endoscopy can be used to manage the complication caused by PC, including endoscopic biliary stent placement for obstructive jaundice, and duodenal stent placement for duodenal obstruction. In addition, in those cases in whom obstructive jaundice failed to be relieved by endoscopic biliary stent placement, EUS-guided biliary drainage has emerged as an alternative procedure. Furthermore, antitumor agents can be delivered into tumor tissue or celiac plexus directly under interventional EUS guided to manage the tumor or the pain caused by the tumor. In this review, the progress in conventional endoscopy and EUS for PC management is discussed.

Radiofrequency ablation for pancreatobiliary disease

PURPOSE OF REVIEW

Radiofrequency ablation (RFA) has been recognized for its potential in palliative treatment for pancreatic cancer as well as malignant biliary strictures. The purpose of this review is to describe the technology, endoscopic technique, and reported outcomes of endoscopic RFA in the management of malignant biliary strictures and unresectable pancreatic cancer.

RECENT FINDINGS

Intraductal biliary RFA is safe and feasible and appears to confer a survival advantage. Pancreatic endoscopic ultrasound-guided RFA is a promising new technique and may result in either resolution of tumor or reduction in size.

SUMMARY

Intraductal biliary RFA and pancreatic endoscopic ultrasound-guided RFA are important modalities in malignant biliary obstruction and unresectable pancreatic cancer. Intraductal biliary RFA should be used as an adjunct to biliary stenting. Further trials are needed to determine if RFA leads to a benefit in pancreatic cancer treatment. Two prospective trials are currently underway to determine if intraductal biliary RFA indeed confers a survival advantage in malignant obstruction.

Endoscopic Ultrasound-Guided Radiofrequency Ablation of the Pancreatic Tumors: A Promising Tool in Management of Pancreatic Tumors

Objective. Radiofrequency ablation is a well-established antitumor treatment and is recognized as one of the least invasive therapeutic modalities for pancreatic neoplasm. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) delivery can be used to treat both pancreatic cancer and asymptomatic premalignant pancreatic neoplasms and may serve as a less invasive alternative to surgical resection. This is an appealing option that may result in less morbidity and mortality. The aim of this review was to summarize and evaluate the clinical and technical effectiveness of EUS-guided RFA of pancreatic neoplasms. Methods. A through literature review was performed to identify the studies describing this novel technique. In this review article, we have summarized human case series. The indications, techniques, limitations, and complications reported are discussed. Results. A total of six studies were included. Overall, a 100% technical success rate was reported in human studies. Complications related to endoscopic ultrasound-guided radiofrequency ablation delivery have been described; however, few cases have presented life-threatening outcomes. Conclusion. We believe that this novel technique can be a safe and effective alternative approach in the management of selected patients.

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.

New Scopes, New Accessories, New Stents for Interventional Endoscopic Ultrasound

Technological advances have rapidly expanded the therapeutic potential of endoscopic ultrasound (EUS). Innovations in stent technology; directed adjunctive therapy for pancreatic tumors, including radiofrequency ablation and fiducial marker placement; advanced imaging modalities, including needle-based confocal laser endomicroscopy; and new echoendoscopes, such as the forward-viewing linear echoendoscope, are emerging as safe and effective tools and devices for providing a broad range of treatments and therapies previously not thought possible. In this review, we summarize and discuss the new echoendoscopes, accessories, and stents for interventional EUS and highlight the recent literature on technical and therapeutic efficacy. The therapeutic role and indications for EUS are rapidly evolving well beyond its current limits as new EUS-specific designed tools are designed, and ultimately, should help achieve the goal of improving patient outcomes.

New developments in endoscopic ultrasound-guided therapies

Endoscopic ultrasound (EUS) has opened new horizons in minimally invasive therapies for diverse gastrointestinal pathologies. Digestive Disease Weak 2015 held in Washington, DC., USA featured exciting research articles on EUS-guided therapeutic procedures. EUS-guided biliary drainage has been attempted and described for many years. There seems to be a lot of interest among various international groups to compare this technique with other alternatives in terms of efficacy and safety. Similarly, EUS-guided pancreatic drainage of cysts and fluid collections continues to evolve with new stents and devices being developed specifically for deployment under endosonographic guidance. EUS-guided ablation of cystic pancreatic tumors is innovative but not always effective. Combining alcohol ablation with injecting chemotherapeutic agents may improve long-term results regarding efficacy. Similarly, for solid pancreatic tumors there appears to be ongoing interest and continuing efforts in injecting different chemotherapeutic or ablative agents, delivering fiducials for radiation guidance and even attempting ablation with radiofrequency. Gastric variceal treatment and EUS-guided anastomoses also continue to be investigated. This review article is focused on the recent developments in EUS-guided therapies presented at Digestive Disease Week (DDW) 2015.