ESTRO 2024 - Abstract Book

S5159

Radiobiology - Immuno-radiobiology

ESTRO 2024

79

Digital Poster

Longitudinal evaluation of lymphoid and myeloid cells of patients treated with chemoradiotherapy

Panagiotis Balermpas 1 , Dilara Sahin 2 , Rebecca Masek 2 , Martina Broglie 3 , Matthias Guckenberger 1 , Onur Boyman 2 , Jens von der Grün 1 1 University Hospital Zurich, Department of Radiation Oncology, Zurich, Switzerland. 2 University Hospital Zurich, Department of Immunology, Zurich, Switzerland. 3 University Hospital Zurich, Department of Otorhinolaryngology Head and Neck Surgery, Zurich, Switzerland

Purpose/Objective:

To prospectively, evaluate longitudinally all common populations of lymphoid and myeloid cells in the peripheral blood of patients treated with definitive chemo-radiotherapy (CRT) for squamous cell carcinoma of the head and neck (SCCHN).

Material/Methods:

Three comprehensive peripheral blood counts of patients treated with bilateral CRT for stage II-IVB SCCHN within a prospective trial were performed at three different time-points (NCT03972072): Prior to therapy (1), after the first week of treatment (2), and three months after treatment completion (3). Isolated cells were assessed by Fluorescence-Activated Cell Sorting (FACS)-analysis. For comparison of a healthy cohort (HC) with patients, unpaired Wilcoxon tests were used. For longitudinal analyses of patient visits were done using paired Wilcoxon tests.

Results:

Twenty-five prospectively recruited patients receiving definitive CRT were included into this study. Tumor patients showed significantly increased levels of myeloid cells (p<0.001) and decreased T-cells (p=0.009) in the peripheral blood compared to the HC. Neutrophil granulocytes were overall reduced in patients compared to HC (p=0.043). Further, CD8-effector memory cells (p<0.001) and NK-cells (p=0.010) significantly increased during treatment and at follow-up compared to baseline for treated patients. Also, FOXP3+/CD4+ regulatory T-cells were generally more abundant in patients (p=0.010) and interestingly became more abundant as a response to CRT (p<0.001).

Conclusion:

We performed a longitudinal analysis of important subpopulations of the innate and adaptive immune system found in the peripheral blood of patients with SCCHN. We identified significant changes longitudinally for patients and differences between HC and patients.

Keywords: head and neck cancer, immune cells, FACS