Transarterial Chemoembolization for Hepatocellular Carcinoma

Abstract

Hepatocellular carcinoma (HCC) is the fifth most common malignancy in the world and is responsible for ~500,000 deaths worldwide annually.1 The incidence almost equals the mortality. It is the most common cause of death in patients with compensated liver cirrhosis. HCC usually arises in the setting of chronic liver disease, commonly from hepatitis B, C, or alcohol abuse. In fact, 80% of HCC arises in the setting of cirrhosis. Despite available treatment, survival rates of HCC remain poor, with an estimation of 54% at 1 year, 40% at 2 years, and 28% at 3 years.2 The only definitive therapy is liver transplantation. Resection, when possible, is not curative as cirrhosis remains a comorbidity. Even with transplantation in early HCC associated with cirrhosis, there is still a potential risk for HCC recurrence.3 Typically, transplantation is reserved for candidates with a single lesion up to 5 cm in diameter, or multiple lesions up to three with a total diameter of 9 cm, with no vascular invasion and no regional or distant nodal metastatic disease. The 4-year survival rate for transplantation is ~80%. Similar survival rates have been reported for larger HCCs.4 With transplantation the only curative option, qualified patients often languish on the waiting list due to the current organ shortage. It has been shown that a 6- to 12-month waiting time for orthotopic liver transplantation (OLT) is associated with reduced overall survival compared with subjects with lesser waiting time due to progression of tumor beyond favorable criteria or due to drop-out for other reasons.5 In fact, the average waiting time can exceed one-year, at which point the drop-out rate is 30 to 40%. Drop-out rate from HCC progression beyond favorable criteria is estimated at 10% at 6 months.6 Surgical resection can increase the OLT rate to 3.7% and 10.7% for a waiting list of 6 and 24 months, respectively. However, surgical resection is associated with significant risks in the setting of cirrhosis, including hemorrhage and hepatic decompensation.7 It is in this setting that other therapies have been developed to treat, though not necessarily cure, patients with HCC to prevent HCC progression and increase the chance of organ transplantation, to downstage patients into favorable criteria for liver transplantation, and to prolong survival and improve quality of life for those who do not qualify for liver transplantation. Therapies that have been in use include transarterial chemoembolization (TACE), ablative therapies (including both thermal and cryoablation), radio embolization, and percutaneous alcohol injection. The focus of this article is on the rationale, technique, and results of TACE in HCC in the setting of cirrhosis.