High intensity focused ultrasound: a noninvasive therapy for locally advanced pancreatic cancer

Abstract

The noninvasive ablation of pancreatic cancer with high intensity focused ultrasound (HIFU) energy is received increasingly widespread interest. With rapidly temperature rise to cytotoxic levels within the focal volume of ultrasound beams, HIFU can selectively ablate a targeted lesion of the pancreas without any damage to surrounding or overlying tissues. Preliminary studies suggest that this approach is technical safe and feasible, and can be used alone or in combination with systemic chemotherapy for the treatment of patients with locally advanced pancreatic cancer. It can effectively alleviate cancer-related abdominal pain, and may confer an additional survival benefit with few significant complications. This review provides a brief overview of HIFU, describes current clinical applications, summarizes characteristics of continuous and pulsed HIFU, and discusses future applications and challenges in the treatment of pancreatic cancer.

Keywords: Focused ultrasound surgery; High intensity focused ultrasound; Hyperthermia; Pancreatic cancer; Therapeutic ultrasound; Thermal ablation.

Figure 1

Schematic diagram demonstrating the principle of high intensity focused ultrasound treatment for pancreatic cancer. Ultrasound beam is focused into a small volume in which ultrasound energy is converted into heat to induce the required coagulation necrosis of a targeted pancreatic tumor. T: HIFU transducer; C: The targeted pancreatic cancer.

Figure 2

Grey-scale changes in a treated pancreatic cancer on real-time ultrasound images during high intensity focused ultrasound exposure. A: Ultrasound (US) image obtained before high intensity focused ultrasound (HIFU) shows a pancreatic cancer lesion present in the body of the pancreas (arrowheads); B: US image obtained immediately after the one-slice HIFU treatment shows the obvious hyperechogenicity of the treated pancreatic tumor (arrowheads).

Figure 3

Contrast-enhanced T-weighted MR images obtained in a patient treated with high intensity focused ultrasound for advanced pancreatic cancer. The tumor was 4.5 cm in diameter and located in the body of the pancreas. A: Image obtained before high intensity focused ultrasound (HIFU) shows blood supply in the pancreatic lesion (arrows); B: Image obtained 2 wk after HIFU shows no evidence of contrast enhancement in the treated lesion (arrows), which is indicative of complete coagulation necrosis in the treated pancreatic cancer.