Disease context Primary liver cancer is the sixth most commonly diagnosed cancer globally and the fourth leading cause of cancer mortality. HCC accounts for 75-95% of all primary liver cancers, with HCC-related mortality rising despite declining overall cancer trends.
Role of TACE Transarterial chemoembolization (TACE) is the standard treatment for intermediate-stage HCC per the Barcelona Clinic Liver Cancer (BCLC) staging system. It is also recommended when other treatments are not feasible at earlier stages, and is used more broadly in Asian clinical practice.
How TACE works TACE combines two effects: direct delivery of cytotoxic agents (such as doxorubicin or cisplatin) into the tumor via the hepatic artery, and embolization that cuts off the tumor's blood supply. This dual mechanism causes both chemical cytotoxicity and ischemic tumor necrosis.
Two techniques There are two main TACE approaches: conventional TACE (cTACE) using lipiodol as an oil-based carrier, and drug-eluting bead TACE (DEB-TACE) using microspheres that release drugs in a sustained manner. Both are widely used, and this review summarizes their comparative evidence and evolving applications.
Comparable tumor response Multiple prospective studies and meta-analyses, including the pivotal PRECISION V and PRECISION ITALIA trials, have consistently shown no significant difference in tumor response, time to progression, or overall survival between cTACE and DEB-TACE.
Safety differences Despite expectations of improved safety with DEB-TACE, adverse event rates are broadly similar between the two techniques. However, DEB-TACE is independently associated with significantly higher rates of liver and biliary injuries (biloma, liver infarction, arterial damage) with an odds ratio of 6.63 for biliary injury.
Post-embolization syndrome The most common adverse event for both techniques is post-embolization syndrome (pain, fever, ileus), occurring in about 47-52% of cTACE patients. DEB-TACE is associated with less post-procedural pain but more locoregional complications.
Novel B-TACE technique Balloon-occluded TACE (B-TACE) is a newer technique from Japan using a microballoon catheter to occlude the feeding artery, resulting in denser drug accumulation in the tumor. Initial retrospective studies suggest superior efficacy versus conventional TACE, but well-designed randomized trials are still needed.
Early-stage HCC When curative treatments (resection, transplantation, ablation) are not feasible due to age, liver dysfunction, comorbidities, or tumor location, TACE can be used for early-stage HCC. Several studies show high response rates and good outcomes in this context.
Bridge and downstaging to transplantation TACE serves as bridge therapy for patients awaiting liver transplantation, reducing dropout from transplant waiting lists to 3-13%. Response to TACE predicts post-transplant outcomes, making it valuable as both a waiting strategy and a means to downstage patients into transplant criteria.
Advanced HCC with portal vein tumor thrombosis Despite being outside guidelines, TACE was used as first-line treatment in nearly 50% of BCLC stage C patients in real-world practice. For selected patients with segmental portal vein thrombosis (PVTT) and preserved liver function, TACE has shown survival benefits over best supportive care.
Decision-making framework The appropriate application of TACE extends across several disease stages and clinical situations. Physicians must balance tumor biology, liver function reserve, and patient performance status when deciding to offer TACE outside its traditional intermediate-stage indication.
ART and ABCR scores The ART score uses AST increase, Child-Pugh score change, and radiologic response to guide retreatment decisions. The ABCR score incorporates AFP, BCLC stage, Child-Pugh change, and tumor response. A score of greater than or equal to 2.5 (ART) or greater than or equal to 4 (ABCR) suggests limited benefit from repeated TACE.
Limitations of scoring systems Neither the ART nor ABCR score has been sufficiently validated to be incorporated into current treatment guidelines. Their predictive value for overall survival has been questioned in multiple studies, and clinical decisions should integrate multiple patient-specific factors rather than relying solely on these scores.
TACE refractoriness criteria The Japan Society of Hepatology (JSH) defines TACE refractoriness based on: two or more consecutive insufficient responses with viable lesion greater than 50%, two or more consecutive increases in tumor number, continuous elevation of tumor markers, or appearance of vascular invasion or extrahepatic spread.
Molecular mechanisms c-MET upregulation following TACE, TP53 pathway mutations, and SIRT7-mediated suppression of p53 have been implicated in TACE refractoriness. Timely recognition of refractoriness and transition to systemic therapy before liver function deteriorates is critical for maintaining treatment options.
TACE plus radiofrequency ablation Sequential TACE followed by radiofrequency ablation (RFA) significantly improves overall survival compared to RFA alone, particularly for tumors larger than 3 cm. For small HCC (2-3 cm), the combination achieves comparable outcomes to surgery, making it an important alternative for non-surgical candidates.
TACE plus radiation therapy A meta-analysis of 11 RCTs and 14 non-RCTs showed TACE plus radiation therapy (RT) significantly improved response and survival versus TACE alone. A randomized trial demonstrated TACE plus RT was superior to sorafenib in advanced HCC patients with macrovascular invasion, offering a new treatment paradigm.
TACE plus anti-angiogenics TACE induces tissue hypoxia that upregulates VEGF, potentially promoting tumor revascularization and recurrence. Despite this rationale, four RCTs combining TACE with sorafenib, brivanib, or orantinib all failed to improve survival. The TACTICS trial succeeded by using TACE-specific endpoints and longer sorafenib administration (38.7 weeks), achieving a median PFS of 25.2 months.
TACE plus immunotherapy Locoregional TACE promotes local inflammation and releases tumor antigens, potentially enhancing immune checkpoint inhibitor activity. Early results with tremelimumab plus TACE showed a 26% partial response rate. Multiple ongoing phase II/III trials (EMERALD-1, PETAL, IMMUTACE) are evaluating TACE combined with PD-1/PD-L1 inhibitors and bevacizumab.
New prognostic models Several scoring systems have been developed to predict survival after TACE. The ALBI-TAE model (combining albumin-bilirubin grade, Up-to-11 criteria, and AFP) outperformed prior models. The six-and-twelve score stratifies patients into three prognostic groups with median survival of 49.1, 32.0, and 15.8 months based on the sum of tumor size and number.
TACE-specific prediction tools The Pre-TACE-Predict and Post-TACE-Predict models provide individualized patient survival prediction using routinely available clinical features plus first TACE response (mRECIST). These models classify patients into four risk categories with median OS ranging from 7 months to over 4 years, enabling online calculator-based patient-level prognostication.
Neutrophil-to-lymphocyte ratio (NLR) A high NLR reflects systemic inflammation and predicts poor survival after TACE. Neutrophils promote tumor proliferation, angiogenesis, and metastasis, while lymphocytes suppress tumor progression. NLR combined with platelet-to-lymphocyte ratio (PLR) or C-reactive protein-to-albumin ratio improves survival prediction.
Radiomics and deep learning Radiomics extracts quantitative imaging features from CT or MRI to predict TACE outcomes. CT radiomics signatures including arterial and portal venous phase features independently predict overall survival. Combining radiomics with immunologic biomarkers like NLR may enable personalized treatment planning, though standardization of image acquisition remains a key challenge.
Individualized patient selection The heterogeneity of intermediate-stage HCC demands better selection tools. Integrating tumor burden criteria (six-and-twelve score), liver function (ALBI grade), and biologic markers will help identify the patients most likely to benefit from TACE versus alternative treatments.
Defining and preventing TACE failure Molecular understanding of refractoriness (c-MET, TP53, SIRT7 pathways) may yield predictive biomarkers to identify patients at risk of early TACE failure. Protecting liver function through selective and appropriately timed TACE remains a fundamental principle for preserving downstream treatment options.
Immunotherapy integration The most exciting frontier is combining TACE with immune checkpoint inhibitors. TACE-induced tumor antigen release may prime the immune system to respond to PD-1/PD-L1 blockade, potentially converting localized treatment into a systemic immune response. Phase III results from ongoing trials are eagerly awaited.
Technical evolution Deep learning and radiomics approaches are rapidly maturing but require validation across diverse institutions. Standardization of TACE techniques, imaging protocols, and response criteria will be necessary to enable meaningful cross-study comparisons and clinical adoption of AI-based decision support tools.