Use of high intensity focused ultrasound for treating malignant tumors

Objective To investigate the efficacy and side effects of high intensity focused ultrasound(HIFU) in the treatment of malignant solid tumors. Methods Thirty patients who refused surgery and/or were refractory to chemotherapy were treated by HIFU alone, with the efficacy and side effects monitored as follows: observation of vital organ signs; functional assay of important organs; imaging examinations including: digital subtraction angiography (DSA), CT, MRI, single photon emission computed tomography (SPECT), large core needle biopsy, complications and metastasis. Results After HIFU therapy, the vital signs remained stable and the functions of the heart, lung, kidney and liver were also normal. DSA images showed that small or larger arteries were not damaged. After a follow-up of 10–38 months(mean 23.1 months), 26 patients(87%) were alive. The volume of the tumor underwent complete regression in 10 patients. Shrinkage of the tumor volume 3≽50% was observed in 13 patients. Eight of 13 patients were examined by large core needle biopsy, all showing necrosis and /or fibrosis though3patients(10%) had local recurrence. Two of these were retreated again by HIFU and the locally recurrent tumors were controlled. New metastases developed in 5 patients after HIFU. Two patients suffered from peripheral nerve injuriy and they have recovered during the follow-up. One patient developed skin injury. Conclusion High intensity focused ultrasound is effective and safe in the treatment of malignant solid tumors.