High-intensity focused ultrasound (HIFU): effective and safe therapy for hepatocellular carcinoma adjacent to major hepatic veins

Abstract

Hepatocellular carcinoma (HCC) is an especially frequent malignancy in China. Radiofrequency ablation, percutaneous ethanol injection, transarterial chemoembolization, cryoablation, microwave coagulation, and laser-induced interstitial thermotherapy all offer potential local tumor control and occasionally achieve long-term disease-free survival. High-intensity focused ultrasound (HIFU), as a noninvasive therapy, can be applied to treat tumors that are difficult to treat with other techniques. The preliminary results of HIFU in clinical studies are encouraging. The aims of this investigation were to assess the efficacy of the system in obtaining necrosis of the target tissue and to determine whether HIFU ablation is hazardous to adjacent major blood vessels. Over 7 years, thirty-nine patients with HCC were enrolled in this investigation. The inferior vena cava (IVC), main hepatic vein branches, and the portal vein and its main branches were evaluated. The distance between tumor and main blood vessel was less than 1 cm in all these enrolled patients. Contrast-enhanced MRI was used to evaluate the perfusion of tumors and major blood vessels. We conducted HIFU ablation for the treatment of 39 patients with 42 tumors, with each tumor measuring 7.4+/-4.3 (1.5-22) cm in its greatest dimension. Among the 39 patients, 23 were males and 16 females. The average age was 53.2 years (range 25-77 years). Thirty-seven patients had a solitary lesion, one had two lesions, and the remaining one had three lesions. Nineteen lesions were located in the right lobe of liver, 18 in the left lobe, and 5 in both right and left lobes. Among the 42 tumors, 25 were adjacent to 1 blood vessel, 12 adjacent to 2 main vessels, 2 adjacent to 3 main vessels, and 1 adjacent to 4 main vessels. Twenty-one of the 42 tumors were completely ablated, while the rest of the tumors were ablated by more than 50% of lesion volume after one session of HIFU. No major blood vessel injury was observed in any subject after 23.8+/-17.2 months follow-up. HIFU can achieve complete tumor necrosis even when the lesion is located adjacent to the major hepatic blood vessels. Short-term and long-term follow-up results show that HIFU can be safely used to ablate the tumors adjacent to major vessels.