ESTRO 2024 - Abstract Book

S5285 ESTRO 2024 compared to controls, TP, and BP protons at day 10 and 70. Smaller differences in expression levels were found between the groups at day 35 and 105. Cytokine PCA scores for controls, TP, and BP protons were similar while scores for X-rays differed markedly from the other groups. The first principal component, based on expression levels of the six cytokines at day 10 or 70, showed a marked, significant association with ACD for the X-ray group (r2>0.40), but not for the TP and BP groups. Radiobiology - Normal tissue radiobiology

Figure 1: Standard cytokine score with time after irradiation for MIP-1α, KC, G-CSF, IL-1α, TIMP-1 and TNF. For each treatment category, the score was calculated as the sum of the standard scores (mean centered with unit standard deviation) for each cytokine. C =Controls. BP : Protons, Bragg plan. TP . Protons, transmission plan. X : X-rays.

Conclusion:

Loss of acinar cells in salivary glands and reduced saliva production after irradiation is common after all X-ray and proton irradiations, but protons seem biologically more effective compared to X-rays for these endpoints. However, this was not reflected in cytokine expression levels, where X-rays only triggered a distinct, time dependent cytokine wave that was associated with ACD. This shows that X-rays induced an inflammatory response in salivary glands, possibly accompanying acinar cell loss. Conversely, protons caused a ‘cold’ response with respect to cytokine expression, but still lead to pronounced acinar cell loss. This work illustrates differences in biological responses after X- and proton-irradiation and may for instance impact mitigation strategies targeting radiation-induced inflammation.

Keywords: Protons, cytokines, late effects

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Poster Discussion

Pectin alleviates acute intestinal normal tissue toxicity after exposure to ionising radiation.

Aliu Moomin 1 , Justyna Kaczmarek 2 , Adam Potter 1 , Susan M. Hay 1 , Chee K. Then 3 , Jenna Gregory 2 , Anne E. Kiltie 1