Cancer Immunology: Impact of Radioembolization of Hepatocellular Carcinoma on Immune Response Modulation

Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer and the fourth most common cause of cancer mortality. The tumor microenvironment is increasingly recognized as having a central role in HCC carcinogenesis; factors such as tumor and immune cell interactions, cytokines, and extracellular matrix have key roles. Transarterial radioembolization (TARE) is a locoregional therapy for HCC that not only has a direct tumoricidal effect but also induces an immune response against tumor cells with subsequent immunogenic cell death. This TARE-induced tumor immunogenicity occurs through enhancement of tumor-associated antigen expression and recruitment and diversification of tumor-infiltrating lymphocytes. In addition, immunologic biomarkers, including neutrophil-to-lymphocyte ratio, lymphocyte count, and cytokine levels, may be useful for predicting outcomes after TARE. Early data are promising regarding the potential synergistic benefit of treatment algorithms that combine TARE and immunotherapies, and interest is growing in the clinical application of such combinations. The purpose of this article is to provide an overview of cancer immunology, summarize the available data on the biologic effects of TARE on local and systemic immune responses, and explore the potential role of the combination of TARE and immunotherapy for HCC.