Combining radiotherapy and immunotherapy: a revived partnership.

摘要

Ionizing radiation therapy (RT) is an important local modality for the treatment of cancer. The current rationale for its use is based largely on the ability of RT to kill the cancer cells by a direct cytotoxic effect. Nevertheless, considerable evidence indicates that RT effects extend beyond the mere elimination of the more radio-sensitive fraction of cancer cells present within a tumor at the time of radiation exposure. For instance, a large body of evidence is accumulating on the ability of RT to modify the tumor microenvironment and generate inflammation. This may have far reaching consequences on the response of a patient to treatment, especially if radiation-induced tumor cell kill were to translate into the generation of effective anti-tumor immunity. Although much remains to be learned about how radiation can impact tumor immunogenicity, data from pre-clinical studies provide the proof of principle that different immunotherapeutic strategies can be combined with RT to enhance anti-tumor effects. Conversely, RT could reveal a useful tool to combine with immunotherapy.This article will briefly summarize what is known about the impact of RT on tumor immunity, including tumor-associated antigens, antigen presenting cells, and effector mechanisms. In addition, the experimental evidence supporting the contention that RT can be used as a tool to induce anti-tumor immunity is discussed, and a new approach to radio-immunotherapy of cancer is proposed.