ABSTRACT
Programmed cell death-1/programmed cell death-ligand 1(PD-1/PD-L1) inhibitors have been approved for a variety of tumors, whereas the efficacy as monotherapy is low. How to sensitize the efficacy of PD-1/PD-L1 inhibitors through combined radiotherapy is the current research focus. Multiple studies have demonstrated that the combination of radiotherapy and anti-PD-1/PD-L1 therapy has yielded survival benefits. Nevertheless, ionizing radiation is a double-edged sword for anti-PD-1/PD-L1 therapy. For patients with metastatic cancers, radiotherapy should be fully exerted as a sensitizer to systemic anti-PD-1/PD-L1 therapy and the immunosuppressive effects should be avoided as much as possible. It is closely correlated with the selection of radiation dose, fraction size, treatment timing and irradiated numbers and sites. Therefore, this article reviews how to optimize radiotherapy combined with anti-PD-1/PD-L1 treatment scheduled for advanced stage metastatic cancers.