Pilot study on high-intensity focused ultrasound as a bridging therapy for patients with unresectable/unablatable hepatocellular carcinoma on transplant waiting list

Abstract

Background and objective: Bridging therapy is necessary for patients with unresectable/unablatable hepatocellular carcinoma (HCC) who are on liver transplant waiting list. We have launched a pilot study, which is the first of its kind in the world, to investigate the outcomes of high-intensity focused ultrasound (HIFU) ablation as a bridging therapy for these patients. Patients and Methods: All adult patients with unresectable/unablatable HCC within the UCSF (University of California, San Francisco) criteria waitlisted for liver transplantation at Queen Mary Hospital, the only liver transplant centre in Hong Kong, in the period from January 2011 to June 2012 were screened for suitability for HIFU ablation. Patients not suitable for HIFU ablation were given transarterial chemoembolization (TACE) or best medical treatment, depending on their liver function test results. The study's primary end points are dropout rate and rate of tumour necrosis in explant livers. The secondary end point is short-term (i.e. one-year) survival (overall and disease-free). Results: Seventy-seven patients (HIFU, 23; TACE, 26; best medical treatment, 28) were included in the study. Before the introduction of HIFU ablation, only 33.8% of patients received bridging therapy (TACE only, N = 26). With HIFU ablation in use, the rate increased dramatically to 63.6% (TACE + HIFU, N = 26 + 23). The dropout rate was 14.3% (N = 11) in the HIFU group, 11.7% (N = 9) in the TACE group, and 9.1% (N = 7) in the best medical treatment group (P = 0.235). The overall dropout rate was 35% (N = 27). Comparison of the HIFU and TACE groups found that patients in the former had significantly poorer liver function as reflected by Model of End-stage Liver Disease scoring and Child-Pugh grading. The median percentage of tumour necrosis on explant was 12.5% vs. 40% (p=0.283). Both groups had 100% one-year survival (overall and disease-free). Conclusions: HIFU ablation is a safe and effective bridging therapy, even for Child-Pugh C patients while waiting for liver transplantation.