An Experimental Study of High Intensity Focused Ultrasound on Pig’s Pancreas and the Early Clinical Experience on Pancreatic Cancer

Objective: To investigate the feasibility and safety of high intensity focused ultrasound (HIFU) treatment of in vivo pig pancreases, and to evaluate the safety and efficacy of HIFU in the clinical treatment of pancreatic cancer in humans. Methods: HIFU was performed in 12 domestic pig pancreases in vivo with varying acoustic energies. The safety of HIFU treatments was assessed by necropsy. The pathology and microstructure of the treated pancreases were evaluated using standard histology and transmission electron microscopy. Following the animal studies 62 patients with advanced pancreas cancer were treated with 250 – 420 W of acoustic power. There were 3 patients with stage II, 23 patients with stage III, and 36 patients with stage IV disease. Results: In animal studies, precise regions of coagulation necrosis were identified on pathology in 8 specimens that were treated with 420 W or 645 W acoustic power. Treatment effects were unable to be identified in 4 specimens treated with 300∼340 W acoustic power; however, damages to the cells microstructure and apoptosis were identified on electron microscopy. Damage to the stomach and colon were seen in some animals treated with 645 W. In the clinical treatments in humans the following were seen: local tumor control: complete response (CR) 0%, partial response (PR) 17.7%, no change (NC) 54.8%, progressive disease (PD) 27.5%. Pain relief was achieved in 87.1% of patients. The median survival for stage II and III patients was 11.2 months and median survival for stage IV patients was 5.6 months. The total median survival was 8.6 months. The survival rate at 1 year was as follows: stage II and III 42.3%, stage IV 5.6%. The survival rate at 2 years was as follows: stage II and III 15.4%, stage IV 0%. There were no severe complications or adverse events related to HIFU therapy seen in any of the patients treated. Conclusions: This study supports the feasibility of HIFU in the treatment of pancreatic cancer. The clinical application of HIFU to pancreas cancer was safe and effective especially in palliating pain.