gms | German Medical Science

Background: Salivary gland carcinomas (SGC) are a rare tumor entity that comes along with a high heterogeneity in terms of the histological features, the dignity or the outcome. Therefore, the therapeutic options for SGCs are limited. The inclusion of immunotherapy (IT) however, might improve the outcome of patients suffering from high grade SGCs. In order to integrate IT as therapeutic option for SGC and to facilitate therapeutic decisions based on the tumor (immune) biology, predictive and prognostic immunological biomarkers are indispensable. Therefore, we aim to determine the immune status and microbiome of SGC patients within the scope of the prospective ImmoGlandula trial (NCT06047236). The identified immune matrices might serve as biomarkers to facilitate the grading and characterization of SG tumors or to identify patients with a favourable immune signature that might profit from IT.

Materials and methods: The ImmoGlandula trial is a prospective, non-interventional and non-randomized trial. In the course of the trial, 300 SGC patients will be recruited. For the determination of a longitudinal immune status from peripheral blood, a flow cytometry-based assay is applied. Thus, blood is taken before and 7 days after the surgery, as well as after the radio-chemotherapy (RCT). The serum and plasma of the patients is used for further analyses of soluble immune modulators. Further, potential markers on the metabolome and microbiome are obtained from saliva, stool and tumor swab samples. From the excised tumor tissue a detailed histology and tumor grading, as well as the determination of common immunological markers is performed. Clinical data on the outcome, survival and potential confounding factors will additionally be collected. These analyses will also in part be performed in a control cohort of benign SG tumors and a control cohort of patients undergoing functional surgery in the head and neck area.

Results: The recruitment in the ImmoGlandula started in January 2023. In this interims analysis we will present the results of the first patients enrolled in the intervention and the control cohorts. In detail, we will provide an overview of the clinical patient characteristics and present the analysis of the longitudinal immune status from peripheral blood. We found that the surgery already modulates the frequency and activation of several immune cell populations in the periphery. Further modulations that can be discriminated from the immune modulation induced by the surgery can be detected after the subsequent RCT in the intervention cohort.

Conclusion: The here presented interims analysis shows that the standard therapy of SGC leads to significant modifications of the immune system. In the further course of the trial, these immune modulations will be linked to the local immune status from the tumor tissue, the microbiome composition, as well as to anamnestic clinical factors to determine prognostic immune signatures for SGC.