Unexpected Therapeutic Implications: The Abscopal Effect in the Management of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most diagnosed cancer worldwide and represents the second cause of cancer-related death worldwide, according to the estimates by Global Cancer Observatory in 2020. Its prognosis is strictly associated with neoplastic stage and liver function. Several treatments are involved in the management of HCC, according to its stage and the patients' performance status. The abscopal effect is a particular phenomenon taking place in locally advanced or in metastatic cancer, as a positive off-target result of ionizing radiation at a certain distance from the irradiated zone determining a systemic effect due to the increase in tumor immune response, and resulting in the shrinkage of neoplastic lesions with a subsequent increase in tumor prognosis. If future studies will allow one to master its etiological mechanisms and deliberately trigger them, it could represent a notable weapon in the treatment of hepatocellular carcinoma, particularly at advanced stages, in which sometimes it is able to positively modify the patients' prognosis. The aim of this review is to evaluate the literature available on this intriguing topic and the characteristics of the mechanisms that originate the abscopal effect, the treatments that can elicit this phenomenon, and the possible relevant therapeutic implications.