Introduction: Radiation therapy (RT) does not affect just the DNA molecule as the main
target, but also results as a bystander effect (BSE) and as an abscopal effect (AE). The term
BSE is used when the bystander unexposed cells show all the signs of exposure to the
radiation. These changes are, for example, changes in the translation process and gene
expression, cell proliferation, apoptosis, and cell death. In the case of AE, the event outside
the irradiated area but within the same organism is meant. We talk about spontaneous tumor
regression. Strategies tested in the preclinical studies show some promising results when
combining RT with some approaches that are developed in the field of immunotherapy.
Purpose: The main purpose of the thesis is to review the existing literature on the effects of
RT on the immune system, as it is one of the currently very actual topics in the field of
radiobiology.Methods: This paper is an extensive review of the literature, mainly of a
foreign scientific data on the selected topic, dealing with the effects of RT on the immune
system. Articles were collected from the scientific database Elsevier, PubMed,
ScienceDirect, COBISS, DKUM and Dlib, and through the library lending (O.A.S.E. –
Fachbibliothek Medizin Düsseldorf, IAEA Library UNOV, Universitätsbibliothek
Medizinische Universität Wien). The keywords used in the search engine were an abscopal
effect, radiotherapy, immune system and radiotherapy, bystander effect, and
immunotherapy. Discussion: In the literature, BSE is mentioned for the first time in the
1950s. This effect requires a long-term research and a long-term follow-up of patients.
Clinical studies and cases were described in both in vitro and in vivo situations. Recently,
more and more clinical studies and cases have been describing the successful combination
of RT and immunotherapy and the bystander effects of radiation. The results of these studies
are extremely promising. The negative effects of RT are also described and are associated
with the induction of BSE and genotoxic responses. The scientific database also proposes
new RT approaches, for example, irradiation with heavy particles. Conclusion: Based on
the literature reviewed, it can be concluded that RT has a major impact on the immune
system and that the researches exploring these radiation effects are significantly increasing.
The new treatment approach is increasingly used in the clinics with immunotherapy, through
which the overall survival of oncological patients can be significantly improved and negative
side effects reduced.
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