Hepatocellular carcinoma (HCC) is among of the common malignant tumours in the world, with a global increasing annual incidence, as reported recently. Almost half of this increase has been attributed to hepatitis C virus (HCV), while a minimal or no increase has been related to hepatitis B virus (HBV) or alcoholic liver disease. Untreated HCC has an notoriously poor prognosis, with a median survival of one to eight months and a fiveyear survival of around 3%. Potentially curative surgical therapeutic options include partial hepatic resection with adequate margins and liver transplantation. However, only 30–40% of patients with HCC qualify for surgery, mostly due to advanced disease at presentation and poor hepatic function, rendering the majority of patients eligible only for palliation. Non-surgical palliative management of unresectable HCC has undergone major changes over the past two decades. Improved outcomes may partly be attributed to earlier detection, advances in imaging, more accurate patient assessment and constant development of locoregional therapies. Among locoregional therapies, transcatheter arterial chemoembolisation (TACE) is a minimally invasive approach for palliative treatment of unresectable HCC that, despite its heterogeneity and variations, has been proven to control symptoms and prolong survival. This article will present some classic concepts that define this popular procedure and some future models of advancement for this technique.

Classic Concepts of TACE

TACE, initially launched by Yamada, exploits HCC’s preferential blood supply by the hepatic artery to precisely deliver chemotherapeutic and embolic agents to the tumour, while sparing the surrounding liver parenchyma and avoiding concomitant systemic toxicity. Since TACE was first introduced as a palliative treatment in patients with unresectable HCC, it has become one of the most commonly performed procedures in interventional radiology. Nowadays, chemoembolisation is the preferred treatment for unresectable HCC. Moreover, for unresectable HCC larger than 10cm in diameter, TACE is the only treatment option. TACE is also employed as an adjunctive therapy to liver resection or as a bridge to liver transplantation, as well as prior to radiofrequency ablation.

TACE typically involves the injection of chemotherapeutic agents, with or without lipiodol and embolic agents, into the branch of the hepatic artery that feeds the tumour. The most commonly used chemotherapeutic drug combination includes doxorubicin, cisplatin and mitomycin C, whereas doxorubicin is the most common single agent used. The absolute and relative contraindications to this technique are listed in Table 1. Patient selection is important, as not every patient with HCC may benefit from chemoembolisation. One important aspect in the selection of patients is the presence of adequate liver function. In patients with advanced liver disease, treatment-induced liver failure may offset the anti-tumoural effect or survival benefit of the intervention. Predictors of outcome are related to tumour burden (tumour size, vascular invasion, and alpha-fetoprotein (AFP) levels), liver functional impairment (Child-Pugh, bilirubin, ascites), performance status (Karnofsky index, Eastern Cooperative Oncology Group (ECOG)) and response to treatment. Thus, the best candidates are patients with preserved liver function and asymptomatic lesions without vascular invasion or extrahepatic spread.

In the authors’ institution, before each TACE procedure, all patients undergo a gadoliniumenhanced magnetic resonance imaging (MRI) scan of the liver, preferably with perfusion/diffusion sequences. This will define the extent and viability of tumour and serve as a baseline study to plan future treatment. A dual-phase MRI or computed tomography (CT) are also acceptable but the addition of the diffusion sequences may demonstrate and quantify tumour necrosis. In addition to information regarding tumour viability, cross-sectional imaging may add important details about its vascular supply and invasion. For example, the presence of portal vein thrombosis and/or variant vascular anatomy may alter the embolisation part of the procedure or reduce the procedure time and contrast load. TACE is typically well tolerated, with most patients requiring only one overnight admission for observation. Transient adverse effects are commonly related to the postembolisation syndrome. Most commonly encountered complications of TACE are listed in Table 2. The most common serious adverse events are liver abscess or liver infarction, which occur in approximately 2% of cases each.