Radiation Therapy and its Effects Beyond the Primary Target: An Abscopal Effect

Radiation therapy (RT) has been used for the treatment of various malignancies since decades with curative or palliative intent. RT for primary disease is often used with curative intent while its use in metastatic settings has been essentially palliative. However, in certain malignancies with metastatic disease, RT to primary disease has led to the regression of not only the primary site but also of the metastatic sites, a phenomenon known as "abscopal effect." Keeping in view the positive effects of RT beyond the primary site, we review the clinical utility of RT regarding its abscopal effect.