ESTRO 2024 - Abstract Book

S5189

Radiobiology - Immuno-radiobiology

ESTRO 2024

Conclusion:

The use of JAKi negatively affects the acute anti-tumor immune response during RIT. In addition, JAKi limit already established anti-tumor immune responses. Further experiments are important to elucidate the underlying mechanisms. These experimental results caution against concurrent use of JAKi and RT/ICB.

Keywords: Anti-tumor immunity, Immune checkpoint inhibitors

3173

Digital Poster

Systematic review: the effect of radiotherapy on neutrophils in cancer, pro- vs anti-tumor response

Léon Raymakers 1,2,3 , Thijs Demmers 1,2 , Gert Meijer 2 , Quintus Izaak Molenaar 3 , Patricia Olofsen 1 , Martijn Intven 2 , Jeanette Leusen 1 , Lois Daamen 2,3 1 UMC Utrecht, Center for Translational Immunology, Utrecht, Netherlands. 2 UMC Utrecht, Radiation Oncology, Utrecht, Netherlands. 3 UMC Utrecht, Surgery, Utrecht, Netherlands

Purpose/Objective:

Radiotherapy (RT) initiates a local and systemic immune response which can induce an anti-tumor response and improve immunotherapy efficacy. Neutrophils are among the first immune cells that infiltrate tumors after RT and are suggested to be essential for the initial anti-tumor immune response. However, neutrophils can also exert pro-tumor effects and multiple murine tumor models show that neutrophil depletion improves RT efficacy. In addition, both high levels of circulating as well as tumor infiltrating neutrophils are associated with patient poor outcomes. Furthermore, RT induced neutrophil infiltration could change the composition of the tumor micro environment (TME) in favor of tumor progression. To improve RT efficacy for cancer patients it is important to understand the interplay between RT and neutrophils. This systematic review will discuss how RT affects the infiltration and function of neutrophils in the TME of solid tumors.

Material/Methods:

A systematic search of the Pubmed and Embase databases was conducted. Rayyan was used for article selection. Articles that fulfilled all these criteria were included: direct effect of RT on neutrophils, cancer patients or a cancer model and external beam RT. Studies using combinational therapies were included if results of RT as monotherapy were separately reported.