Cure Alveolar Soft Part Sarcoma International (iCureASPS)

Abstract

The abscopal effect is mediated by a systemic anti-tumor immune response and reflects the regression of non-irradiated metastatic lesions at a distance from the primary site of irradiation. This review will focus on understanding the biological rationale behind the abscopal effect of radiotherapy (RT), which has a recently renewed interest as a result of the successes achieved with immunotherapy and RT in combination. Both RT and immunotherapy are standard components of modern treatment regimens. Combination of these two modalities results in an increased response in the irradiated lesions themselves and the metastatic regions distant from the site of irradiation. We will summarize the abscopal effect of radiotherapy, in particular, the synergistic effect of RT and immunotherapy.

Keywords: abscopal effect, immunotherapy, radiotherapy

https://www.ncbi.nlm.nih.gov/pmc/articl ... po=1.85185

Introduction and background

Radiotherapy (RT) is a treatment modality which is used to achieve local control of the irradiated area. However, there may be a tumor response in areas where RT has not been performed. This phenomenon is called the abscopal effect of radiotherapy. However, the biological mechanism underlying this effect is not yet clear.

The direct and indirect effects of radiation on deoxyribonucleic acid (DNA) are the primary mechanism responsible for the cytotoxic effects of radiotherapy. In addition to the direct cytotoxic effect on tumor cells, the impacts on the immune system have also been the subject of studies for so long. These effects on the immune system can result in an immune-mediated anti-tumor response. However, a limited number of cases with abscopal effect have been reported where RT was performed solely.

Abstract

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.

Keywords: radiation therapy, abscopal effect, immunomodulation, curative intent, metastatic disease, immunotherapy

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6476619/