An Innovative Approach to Multimodal Cancer Treatment: Combining Radiotherapy and Immunotherapy

Immunotherapy is a promising modality of cancer treatment that has shown encouraging results in patients with a variety of tumor types, most notably in metastatic melanoma. Durableresponses seen in a minority of patients are impressive, and have led to the search for adjunctive therapies to increase response rates. Radiotherapy is capable of inciting inflammation and increasing T cell infiltration in tumors, making it an attractive candidate for combination therapy. The synergy between radiotherapy and immunotherapy has been described for checkpoint inhibitors in a small number of patients. Furthermore, total body irradiation has been used in adoptive cell transfer protocols with improved outcomes. While these therapies are in the early stages of clinical application, definitive studies are needed to clarify the role of combining radiotherapy with immunotherapy. We review the current evidence for these combinations and highlight ongoing studies of these multimodal approaches to cancer therapy.