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

SIMPLE SUMMARY: Regardless of treatment, the overall 5-year survival rate for patients with pancreatic adenocarcinoma is less than 5%. The aim of this preclinical study was to evaluate the feasibility of intraoperative focused ultrasound ablation of the pancreas under Doppler guidance to treat the pancreatic parenchyma and tissues surrounding the superior mesenteric vessels in vivo in a pig model. Large and homogeneous destruction of the pancreatic parenchyma and tissues around the peripancreatic artery without spasm or occlusion by focused ultrasound during an open procedure was feasible without organ penetration. Ultrasound guidance allows for the objective evaluation of the actual treated region. This method could aid in the treatment of locally advanced pancreatic adenocarcinoma that is inaccessible by other known therapeutic methods. The device presented herein is simple to use, reliable and adaptable to local conditions. Such a treatment may also be used in conjunction with resection. 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.