The Future of RT and Immunotherapeutics (Immune Checkpoint Blockade and CAR T-Cells)

Cancer immunotherapies have gained tremendous traction in recent years due to remarkable responses in some patients, with more and more previously incurable patients obtaining prolonged disease remission. These therapies include immune checkpoint inhibitors and CAR T-cells. Unlike all other therapies to date, they rely entirely on the patient’s own immune cells, specifically T-cells, to eliminate the tumor. Why some patients exhibit dramatic responses while others exhibit rapid failure depends on such factors as the pre-existing health of the patient’s T-cells, prior activation history, and disease or therapy-induced phenotype, as well as molecules expressed by the tumor and factors present in the tumor microenvironment. Radiation therapy has the capacity to modulate many of these elements. The complexity of radiation’s influence, such as dose, fractionation, timing, and target volume, on each relevant immune component is only beginning to be understood. As the field of immunotherapy grows in importance and effectiveness, the field of radiation oncology has the opportunity to coevolve to optimally apply its advanced technological capacities toward further vitalizing these novel, exciting therapies.