Riccardo Lencioni

The endpoint in cancer research is overall survival. Nonetheless, other potential surrogate endpoints, such as response rate and time to progression, are currently used. Measurement of response rate in hepatocellular carcinoma (HCC) has become a controversial issue. The World Health Organization (WHO) criteria underestimate the actual response rate; thus, they were amended in 2000 by a panel of experts convened by the European Association for the Study of the Liver (EASL) to take into account treatment-induced tumor necrosis. Applying these guidelines, there was an association between response rate and outcome prediction. More recently, the Response Evaluation Criteria in Solid Tumors (RECIST) guideline was proposed as a method for measuring treatment response based on tumor shrinkage, which is a valuable measure of antitumor activity of cytotoxic drugs. This method was initially adopted by regulatory agencies, such as the U.S. Food and Drug Administration (FDA), for drug approval. However, anatomic tumor response metrics can be misleading when applied to molecular-targeted therapies or locoregional therapies in HCC. In 2008, a group of experts convened by the American Association for the Study of Liver Diseases (AASLD) developed a set of guidelines aimed at providing a common framework for the design of clinical trials in HCC and adapted the concept of viable tumor-tumoral tissue showing uptake in arterial phase of contrast-enhanced radiologic imaging techniques-to formally amend RECIST. These amendments conformed the AASLD-JNCI (Journal of the National Cancer Institute) guidelines and are summarized and clarified in the current article. They are referred to herein as the modified RECIST assessment (mRECIST). Further studies are needed to confirm the accuracy of this measurement compared with conventional gold standards such as pathologic studies of explanted livers.

The design of clinical trials in hepatocellular carcinoma (HCC) is complex because many patients have concurrent liver disease, which can confound the assessment of clinical benefit. There is an urgent need for high-quality trials in this disease. An expert panel was convened by the American Association for the Study of Liver Diseases to develop guidelines that provide a common framework for designing trials to facilitate comparability of results. According to these guidelines, randomized phase 2 trials with a time-to-event primary endpoint, such as time to progression, are pivotal in clinical research on HCC. Survival remains the main endpoint to measure effectiveness in phase 3 studies, whereas time to recurrence is proposed as an appropriate endpoint in the adjuvant setting. Because progression-free survival and disease-free survival are composite endpoints, they are more vulnerable than others in HCC clinical studies and may not be able to capture clinical benefits. Selection of the target population should be based on the Barcelona Clinic Liver Cancer staging system. New drugs should be tested in patients with well-preserved liver function (Child-Pugh A class). Patients assigned to the control arm should receive standard-of-care therapy, that is, chemoembolization for patients with intermediate-stage disease and sorafenib for patients with advanced-stage disease. Further research is needed to incorporate biomarkers and molecular imaging into clinical research in HCC. These surrogate markers may help to enrich study populations and maximize the cost-benefit ratio of trial execution. Design and conduct of phase 3 trials should be coordinated by centers with appropriate expertise in HCC.

Transcatheter arterial chemoembolization (TACE) offers a survival benefit to patients with intermediate hepatocellular carcinoma (HCC). A widely accepted TACE regimen includes administration of doxorubicin-oil emulsion followed by gelatine sponge-conventional TACE. Recently, a drug-eluting bead (DC Bead) has been developed to enhance tumor drug delivery and reduce systemic availability. This randomized trial compares conventional TACE (cTACE) with TACE with DC Bead for the treatment of cirrhotic patients with HCC. Two hundred twelve patients with Child-Pugh A/B cirrhosis and large and/or multinodular, unresectable, N0, M0 HCCs were randomized to receive TACE with DC Bead loaded with doxorubicin or cTACE with doxorubicin. Randomization was stratified according to Child-Pugh status (A/B), performance status (ECOG 0/1), bilobar disease (yes/no), and prior curative treatment (yes/no). The primary endpoint was tumor response (EASL) at 6 months following independent, blinded review of MRI studies. The drug-eluting bead group showed higher rates of complete response, objective response, and disease control compared with the cTACE group (27% vs. 22%, 52% vs. 44%, and 63% vs. 52%, respectively). The hypothesis of superiority was not met (one-sided P = 0.11). However, patients with Child-Pugh B, ECOG 1, bilobar disease, and recurrent disease showed a significant increase in objective response (P = 0.038) compared to cTACE. DC Bead was associated with improved tolerability, with a significant reduction in serious liver toxicity (P < 0.001) and a significantly lower rate of doxorubicin-related side effects (P = 0.0001). TACE with DC Bead and doxorubicin is safe and effective in the treatment of HCC and offers a benefit to patients with more advanced disease.