Open Access

Ehab Shiban, Philipp Krauss, Tina Schaller, Ina Konietzko, Tatiana Mögele, Nicola Jungbäck, Dorothee Mielke, Bruno Märkl, Klaus-Henning Kahl, Zuzanna Mielewczyk, Friederike Liesche-Starnecker

• Malignant brain tumors, including gliomas and brain metastases, present therapeutic challenges due to their aggressive nature and high recurrence rates. Intraoperative radiotherapy (IORT) is a promising novel therapeutic approach that delivers immediate irradiation to the resection cavity. This may trigger a local and systemic immune response. However, the immunological effects of IORT remain poorly understood. Objectives: To investigate the immunomodulatory effects of IORT by analyzing perioperative profiles of inflammatory mediators (IMs) in patients undergoing surgical resection of malignant brain tumors. Design: A prospective observational cohort study comparing IM responses in patients undergoing brain tumor resection with and without IORT. Methods: In total, 44 patients undergoing surgical resection of brain tumors were included, with 20 receiving IORT and 24 serving as controls without IORT. In both groups, cerebrospinal fluid/wound fluid samples were collected from theMalignant brain tumors, including gliomas and brain metastases, present therapeutic challenges due to their aggressive nature and high recurrence rates. Intraoperative radiotherapy (IORT) is a promising novel therapeutic approach that delivers immediate irradiation to the resection cavity. This may trigger a local and systemic immune response. However, the immunological effects of IORT remain poorly understood. Objectives: To investigate the immunomodulatory effects of IORT by analyzing perioperative profiles of inflammatory mediators (IMs) in patients undergoing surgical resection of malignant brain tumors. Design: A prospective observational cohort study comparing IM responses in patients undergoing brain tumor resection with and without IORT. Methods: In total, 44 patients undergoing surgical resection of brain tumors were included, with 20 receiving IORT and 24 serving as controls without IORT. In both groups, cerebrospinal fluid/wound fluid samples were collected from the resection cavity at several predefined intraoperative and postoperative time points. A multiplex proteomic assay was used to measure 19 IM involved in inflammation and immune activation. Results: IORT significantly increased the levels of seven IM (interleukin (IL)-1β, IL-6, IL-8, IP-10, MCP-1, MIP-1β, and VEGF) within the IORT group compared to baseline levels. When comparing to the non-IORT group, the increase in IL-1β was significantly greater for patients with metastases, while IL-10 also showed a trend toward significance. Conclusion: IORT induces distinct changes in levels of IM, which may contribute to improved tumor control. These findings provide novel insights into the immunomodulatory effects of IORT and may have implications for optimizing multimodal treatment strategies for malignant brain tumors. As an exploratory study with a limited sample size, the findings should be interpreted as hypothesis-generating.…