Radiation therapy and cancer treatment: From the basics to combination therapies that ignite immunity

Since its inception in the late nineteenth century, radiation therapy has been a mainstay in the clinic to treat and palliate patients afflicted with cancer. With the rapid advancement in technology for radiation therapy equipment, delivery has improved and late sequalae have been minimized. Alongside the technological advancements, several groundbreaking biological discoveries have enabled scientists to delineate the cellular and molecular implications of radiation exposure. With a greater understanding of the cellular and coordinated tissue responses to irradiation, it became apparent that radiation can influence the activation state of the immune system. In recent years, strategies to enhance the biological response to tumors after radiation therapy have led to combination therapies that stimulate the immune system. Harnessing the specificity and efficiency of the immune system after radiation therapy offers potential for mobilizing the body's innate defense system. This chapter will focus on the rationale for coupling radiation therapy and immunotherapy, and will provide evidence of its efficacy in preclinical and clinical studies.