Impact of the use of systemic corticosteroid therapy on the effectiveness of immune checkpoint inhibitors

Immunotherapy, which consists in using molecules targeting the immune system, has existed for many years in oncology (vaccines, interleukins, monoclonal antibodies) but has recently expanded due to the development of immune checkpoint inhibitors. These monoclonal antibodies help to restore the immunity against cancer by specifically targeting some immune checkpoints such as CTLA-4, PD-1 and PD-L1. Furthermore, in oncology, it is common to use systemic corticosteroids in the management of symptoms linked to the natural history of the disease (pain, spinal cord compression, cerebral edema) and toxicities linked to anticancer treatment. The impact of corticosteroids on the efficacy of immune checkpoint inhibitors is still poorly understood and they should be used cautiously. According to previously published studies, there seems to be a deleterious effect of corticosteroid therapy on the efficacy of immune checkpoint inhibitors when administered before or at the initiation of immunotherapy, while this effect does not seem present when corticosteroids are administered to patients already undergoing immunotherapy. The aim of this work is to analyze the existing data evaluating the impact of corticosteroid use of on the efficacy of immune checkpoint inhibitors.