Intraoperative HIFU Ablation of the Pancreas Using a Toroidal Transducer in a Porcine Model. The First Step towards a Clinical Treatment of Locally Advanced Pancreatic Cancer

Abstract

Apart from palliative chemotherapy, no other therapy has been proven effective for the treatment of locally advanced pancreatic tumors. In this study, an intraoperative high-intensity focused ultrasound (HIFU) device was tested in vivo to demonstrate the feasibility of treating the pancreatic parenchyma and tissues surrounding the superior mesenteric vessels prior to clinical translation of this technique. Twenty pigs were included and treated using a HIFU device equipped with a toroidal transducer and an integrated ultrasound imaging probe. Treatments were performed with energy escalation (from 30 kJ to 52 kJ). All treatments resulted in visible (macroscopically and in ultrasound images) homogeneous thermal damage, which was confirmed by histology. The dimensions of thermal lesions measured in ultrasound images and those measured macroscopically were correlated (r = 0.82, p < 0.05). No arterial spasms or occlusion were observed at the lowest energy setting. Temporary spasm of the peripancreatic artery was observed when using an energy setting greater than 30 kJ. The possibility of treating the pancreas and tissues around mesenteric vessels without vascular thrombosis holds great promise for the treatment of locally advanced pancreatic cancers. If clinically successful, chemotherapy followed by HIFU treatment could rapidly become a novel treatment option for locally advanced pancreatic cancer.

Pancreatic Ductal Adenocarcinoma: Current and Emerging Therapeutic Uses of Focused Ultrasound

“…At lesion borders or regions where immediate cell death is not induced, the phenomenon of thermal fixation may occur, where lower but still lethal thermal exposure is present, leaving tissue architecture intact and leading to cell death typically within 2–3 days [ 22 , 61 ]; while lysis of pancreatic cells has potential to release autodigestive enzymes, leading to pancreatitis, pancreatic cells that experience thermal fixation will not undergo lysis until the intracellular enzymes have been completely denatured and inactivated, which may reduce the risk of pancreatitis with HIFU therapy [ 61 , 62 ]. The feasibility of intraoperative HIFU ablation of pancreatic parenchyma has been demonstrated in porcine models without severe acute pancreatitis or serious intra-abdominal complications [ 63 ], including the use of ultrasound imaging for treatment guidance and evaluation of treated regions [ 64 ].…”