Radiation-induced bystander and abscopal effects: important lessons from preclinical models
Résumé
Radiotherapy is a pivotal component in the curative treatment of patients with localised cancer and isolated metastasis, as well as
being used as a palliative strategy for patients with disseminated disease. The clinical efficacy of radiotherapy has traditionally been
attributed to the local effects of ionising radiation, which induces cell death by directly and indirectly inducing DNA damage, but
substantial work has uncovered an unexpected and dual relationship between tumour irradiation and the host immune system. In
clinical practice, it is, therefore, tempting to tailor immunotherapies with radiotherapy in order to synergise innate and adaptive
immunity against cancer cells, as well as to bypass immune tolerance and exhaustion, with the aim of facilitating tumour
regression. However, our understanding of how radiation impacts on immune system activation is still in its early stages, and
concerns and challenges regarding therapeutic applications still need to be overcome. With the increasing use of immunotherapy
and its common combination with ionising radiation, this review briefly delineates current knowledge about the non-targeted
effects of radiotherapy, and aims to provide insights, at the preclinical level, into the mechanisms that are involved with the
potential to yield clinically relevant combinatorial approaches of radiotherapy and immunotherapy