Precision Locoregional Therapies for Hepatocellular Carcinoma: Percutaneous Ablation and Radiotherapy

Locoregional therapies for hepatocellular carcinoma (HCC) have added flexibility in the patient care by accommodating various clinical issues that limit indication for surgical therapies and/or to enhance therapeutic benefit of other modalities. Percutaneous ablation such as radiofrequency and microwave ablation can achieve good local tumor control less invasively compared to surgical resection and therefore is applicable to inoperable cases due to impaired liver function and other reasons. Supporting techniques such as artificial fluid infusion can mitigate difficulty in ablating tumors close to hepatic hilum/dome and neighboring organs such as the intestine. New ablation modalities such as cryoablation have been developed as alternative options. New radiotherapeutic techniques such as stereotactic ablative radiotherapy and charged particle therapy have been utilized as additional options of locoregional treatment. Radiotherapies can expand treatment indication for locally advanced tumors with portal venous tumor thrombus and/or large size, which cannot be treated with surgical or percutaneous therapies. Immunomodulatory effects of locoregional therapies have rationalized clinical testing of combination with immuno-oncology agents such as immune checkpoint inhibitors to further enhance their antitumor effect. Locoregional therapies will remain the major components of HCC treatment algorithms that assist precision care of the patients optimized for each specific clinical scenario and geographic diversity in patient demographics with the recent technological development, identification of prognosis factors, and characterization of adverse effects.