Immune effects of stereotactic ablative radiation therapy in patients with malignant tumors: literature review

The purpose of the study was to conduct a systematic analysis of the data available in the modern literature on the systemic (abscopal) effects in radiation therapy, which are mediated by immunological phenomena. Material and Methods. A structured search for articles published in peer-reviewed journals between January 2000 and February 2019 was conducted using MEDLiNE database. The review included data from registered clinical trials at Clinicaltrials.gov, showing the results of the combined use of immunotherapy and radiation therapy. Results. There is an opinion that the systemic effect of radiotherapy is mediated by immunological phenomena. in connection with the recent data, there is a growing interest in the combined use of immunotherapy with radiation therapy in order to increase the efficacy of systemic therapy. However, the incidence of abscopal effects after standard radiation treatment is very low. in this regard, stereotactic ablative radiotherapy, due to its high immunogenic potential, low toxicity and short duration of the treatment, is apparently an attractive partner for immunotherapy in patients with metastatic disease. Conclusion. in view of the variety of the immunological effects of radiotherapy, further studies of the effect of radiation therapy on the immune system of cancer patients are needed, and the use of various combinations of immunotherapy and radiation therapy should be continued. All this, ultimately, will help improve the survival rates of cancer patients.