Using Preclinical Data to Design Combination Clinical Trials of Radiation Therapy and Immunotherapy

Immunotherapies are rapidly entering the clinic as approved treatments for diverse cancer pathologies. Radiation therapy is an integral partner in cancer therapy, commonly as part of complicated multimodality approaches that optimize patient outcomes. Preclinical studies have demonstrated that the success of radiation therapy in tumor control is due in part to immune mechanisms, and that outcomes following radiation therapy can be improved through combination with a range of immunotherapies. However, preclinical models of cancer are very different from patient tumors, and the way these preclinical tumors are treated is often very different from standard of care treatment of patients. This review examines the preclinical and clinical data for the role of the immune system in radiation therapy outcomes, and how to integrate preclinical findings into clinical trials, using ongoing studies as examples.