Is an immune-oriented use of radiation therapy possible? An increasingly open question under the spotlight of immunotherapy

Historically, radiation therapy has been devoted to the achievement of local control both in early and advanced disease, palliation of symptoms (i.e. pain), and the treatment of cancer complications (i.e. bone fractures, bleeding) in advanced/metastatic cancer. Recently, the discovery of the role of radiation therapy as a trigger to activate the immune system has led to an increased interest among insiders regarding the interaction between radiation therapy and host immune reactions. The immune systemic effects of radiation therapy are widely acknowledged to be both immunosuppressive and immunostimulant, albeit there exists considerable uncertainty regarding the doses/fraction that can induce them. The main aim of this brief paper is to describe the systemic anti-tumor responses following radiation therapy on the basis of selected doses/fraction.