Role of radiosensitizers, radioprotectors, and radiation mitigators in radiation therapy

Radiation is used in the treatment of a broad range of malignancies. Exposure of normal tissues to radiation may result in both acute and chronic toxicities that can result in an inability to deliver the intended therapy, a range of symptoms, and a decrease in the quality of life. Radiation therapy kills cancer cells by damaging their deoxyribonucleic acid. There are different types of radiation therapy for different malignancies. Radiation therapy can also deteriorate the normal cells, leading to side effects. A radiation countermeasure that can be used before radiation exposure to protect the population from the harmful effects of radiation exposure remains a major unmet medical need and is recognized as an important area for research. There are certain compounds that act to increase the radiosensitivity of tumor cells or to protect the normal cells from the effect of radiation termed as radiosensitizers and radioprotectors. Other agents termed mitigators may be used to minimize toxicity even after radiation has been delivered. The aim of this article is to critically review the available compounds used as radiosensitizers, radioprotectors, and mitigators for different types of cancers.