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

Abstract

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-guided solid pancreatic tumor ablation

“…The healthy external area is unaffected by the ablation. [ 6 7 ] The direct cellular injury depends on different aspects of the target tissues, including the thermal energy applied, the rate of application, and the thermal sensitivity. [ 6 ]…”

“…Indirect delayed damage is also possible, even after termination of thermal ablation; it includes apoptosis, vascular damage, cytokine release, and immunostimulation, with increased peripheral blood stream levels of neutrophils, macrophages, dendritic cells, and lymphocytes. [ 6 7 8 ] Pro-inflammatory cytokines and other cellular contents released after thermal damage could trigger a cascade of immune-mediated events with supplementary antitumoral action. [ 6 ]…”

“…The heat sink effect (blood vessel perfusion-mediated cooling) is reduced in this system, but despite an overall minor ablative capacity, heat injury of the lesion occurs more quickly and there is less damage to the surrounding normal tissue. [ 1 6 7 ]…”

“…The blending of the two different energies could overcome the limits of bipolar systems, which provide less collateral heat damage than monopolar systems despite a lower overall ablative capacity and may increase the effect of the two single modalities. [ 7 18 ] The currently available probe for EUS-guided cryotherm ablation was developed by Erbe Elektromedizin GmbH (Tübingen, Germany). This probe uses an EUS-FNA needle with a sharp distal tip containing two interstitial electrodes that form the current closed system.…”

Review on diagnosis of acute pancreatitis

“…The inflammatory process may be limited to the pancreatic gland with edema or necrosis, or it may involve the surrounding tissues and/or distant organs, hence the clinical manifestations range from mild abdominal pain to very serious presentations 2 . Acute pancreatitis is mild and resolves itself without serious complications in 80% of the patients, but it has complications and mortality in about 20% of the patients despite the aggressive intervention 3 .…”