High-intensity focused ultrasound treatment for advanced pancreatic cancer

Abstract

Pancreatic cancer is under high mortality but has few effective treatment modalities. High-intensity focused ultrasound (HIFU) is becoming an emerging approach of noninvasively ablating solid tumor in clinics. A variety of solid tumors have been tried on thousands of patients in the last fifteen years with great success. The principle, mechanism, and clinical outcome of HIFU were introduced first. All 3022 clinical cases of HIFU treatment for the advanced pancreatic cancer alone or in combination with chemotherapy or radiotherapy in 241 published papers were reviewed and summarized for its efficacy, pain relief, clinical benefit rate, survival, Karnofsky performance scale (KPS) score, changes in tumor size, occurrence of echogenicity, serum level, diagnostic assessment of outcome, and associated complications. Immune response induced by HIFU ablation may become an effective way of cancer treatment. Comments for a better outcome and current challenges of HIFU technology are also covered.

Figure 1

The number of publications and advanced pancreatic cancer patients treated with HIFU or in conjunction with chemotherapy or radiotherapy from 2001 to 2013.

Figure 2

Summary of the complications found in HIFU ablation for advanced pancreatic cancer.

Figure 3

Large rim-enhancing areas of fat necrosis (arrow head) and vertebral body necrosis (arrow) along the ultrasound propagation path in a pancreatic cancer patient two weeks after HIFU ablation in fat-saturated T1-weighted magnetic resonant image after gadolinium infusion (used with permission [7]).

Figure 4

Necrosis (asterisk) in the pancreas head with rim enhancement, a fistula between the pancreatic tumor and the adjacent bowel with the mottled air densities (long thin arrows), and communication between the duodenum and the ablated cavity via focal disruption of the duodenal stent (arrowhead) in a follow-up CT after HIFU ablation (used with permission [7]).

Figure 5

CT imaging shows no apparent change of pancreas (a) before and (b) after HIFU therapy (used with permission [18]).

Figure 6

Dynamic contrast-enhanced gradient-echo T1-weighted MR images (a) before and (b) 2 weeks after HIFU ablation for advanced pancreatic cancer with a diameter of 4.5 cm. No evidence of contrast enhancement in the treated lesion (arrowhead) illustrates complete coagulation necrosis (used with permission [19]).

Figure 7

Sonography of pancreatic cancer (a) before and (b) after HIFU therapy showing the enhancement of echogenicity in the tumor but decrease of vascularity, an indicator of coagulative necrosis (used with permission [20]).

Figure 8

A PET-CT scan made (a) before HIFU demonstrates a SUVmax of  7.5 g/mL and (b) 3 months after HIFU demonstrates coagulative necrosis inside the tumor and the decreased SUVmax of 5.3 g/mL (used with permission [21]).

Figure 9

H&E staining of pancreatic cancer after HIFU ablation shows (a) disappearance of nuclei and necrosis and (b) the thermally fixed cancer cells (used with permission [22]).

Figure 10

Summary of the complications found in the combination of HIFU ablation with chemotherapy and radiotherapy for advanced pancreatic cancer.