Radiotherapy and immune response: the systemic effects of a local treatment

Abstract

Technological developments have allowed improvements in radiotherapy delivery, with higher precision and better sparing of normal tissue. For many years, it has been well known that ionizing radiation has not only local action but also systemic effects by triggering many molecular signaling pathways. There is still a lack of knowledge of this issue. This review focuses on the current literature about the effects of ionizing radiation on the immune system, either suppressing or stimulating the host reactions against the tumor, and the factors that interact with these responses, such as the radiation dose and dose / fraction effects in the tumor microenvironment and vasculature. In addition, some implications of these effects in cancer treatment, mainly in combined strategies, are addressed from the perspective of their interactions with the more advanced technology currently available, such as heavy ion therapy and nanotechnology.

Care of immunocompromised patients with head and neck cancer during the COVID‐19 pandemic: Two challenging and informative clinical cases

“…Although surgery may put the patient at acute risk for exposure to COVID-19, chemotherapy may result in further immunosuppression, and radiotherapy typically requires daily visits to an outpatient clinic over a period of 5 to 7 weeks. [20][21][22][23][24][25] The latter will increase the potential exposure to SARS-CoV-2. The overall risk to the immunocompromised patient of acquiring a COVID-19 infection is probably greater with radiation therapy with or without chemotherapy than after a single visit to the hospital for surgery, even if that one visit requires tracheostomy and hospitalization.…”

The Impact of Locoregional Treatment on Response to Nivolumab in Advanced Platinum Refractory Head and Neck Cancer: The Need Trial

“…In fact, while lymph nodes have a central role in immune response induction, the systemic effect of their dissection is still uncertain, resulting both in enhancement and disempowerment of the immune response in the gut system and head-neck region, respectively [31]. Additionally, radiation therapy could enhance the immunosuppressive effect deriving from surgery and, contemporarily, trigger a systemic immune response through the radiation-induced immunological cell death [32]. Indeed, radiotherapy can act as an in situ vaccine in patient with irradiated tumor, through the induction of anti-tumor T-cell response.…”

Association of Bacteroides acidifaciens relative abundance with high-fibre diet-associated radiosensitisation

“…This could be achieved by oral gavage of B. acidifaciens with or without other bacteria in gnotobiotic mice and in vitro culture studies of B. acidifaciens. As both gut bacteria (35) and irradiation (36) directly interact with the immune system, further in vivo studies need to be conducted in an immune competent model to reveal how immunomodulation might contribute to the radiosensitisation.…”