Acute Radiation Syndrome at Crossroads of Protection and Therapy

Exposure to radiation (>1Gy) induced acute radiation syndrome (ARS), reducing individual defense against exogenous and endogenous factors, resulting in infections and organs dysfunction. Since < 40% of cancer patients require radiation therapy for management, developing acute radiation toxicity, manifesting during or developing months to years after completion. The development of radiation countermeasure to treat ARS patient has been the subject of intense research since World War II. Individual radiation toxicity is assessed by the time gap of onset, severity of nausea and vomiting, and decline in absolute lymphocyte count, over several hours or days after exposure. Numerous synthetic and natural products though evaluated, however, unwanted toxicity even with optimal doses has precluded their usage. Therefore, systematic screening approach is recommended to identify potential new drugs for mitigation of radiation injury. Sincere efforts have been put in the current review to process preclinical to clinical trials, FDA approved treatment modalities and drugs. Therapy includes treatment with hematopoietic cytokines; blood transfusion; and, stem-cell transplantation, in selected cases. Discussions on medical management, of presenting clinical symptoms and signs, envisage the use of radiomimetic, immune-modulatory and anti-inflammatory agents.