ESTRO 2025 - Abstract Book

S702

Clinical - CNS

ESTRO 2025

References: (1) Niyazi M, et al. ESTRO-EANO guideline on target delineation and radiotherapy details for glioblastoma. Radiother Oncol. 2023 Jul;184:109663. doi: 10.1016/j.radonc.2023.109663. Epub 2023 Apr 13. PMID: 37059335.

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Digital Poster The impact of antineoplastic therapy before and after WBRT for non-small cell lung cancer and breast

cancer patients with meningeosis carcinomatosa Michael Schmeling, Claus Belka, Silke Nachbichler Department of Radiation Oncology, LMU Clinic, Munich, Germany

Purpose/Objective: Meningeosis carcinomatosa (MC) is a severe cancer manifestation of the cerebral and spinal meninges, leading to a variety of neurological symptoms. While spinal and whole brain radiation therapy extended to the caudal margin of the second vertebral body (C2 WBRT), systemic targeted therapy as well as chemotherapy and intrathecal chemotherapy can provide benefits in symptom control, overall survival rates remain limited. Material/Methods: In this study, 99 newly diagnosed MC patients who received C2-WBRT at LMU Hospital Munich between October 2001 and July 2023 were analyzed. Among these, 47 patients had non-small cell lung cancer (NSCLC), and 52 patients had breast cancer (BC). The most common fractionation schemes were 5/25Gy and 3/30Gy. Furthermore, we analyzed the role of antineoplastic therapy 12 months prior to or after completing C2-WBRT. Kaplan-Meier method and log-rank test were employed to analyze survival differences between groups. The primary outcome parameter was overall survival. Results: Patients receiving antineoplastic therapy prior to or after C2-WBRT demonstrated improved overall survival (239 days) compared to those without antineoplastic therapy (72 days) (p<0.001). For NSCLC patients, the addition of antineoplastic therapy to C2-WBRT resulted in a median survival of 165 days, compared to 41 days for those without (p<0.001). However, there was no difference in overall survival (p=0.657) when comparing systemic versus intrathecal treatment parallel to C2-WBRT for NSCLC patients. In the BC cohort, those receiving antineoplastic therapy before or after C2-WBRT had a median survival of 291 days, compared to 99 days for those without additional therapy, though this difference lacked statistical significance (p=0.059). Median survival rates for BC patients were 305 days for the C2-WBRT + systemic treatment cohort, 75 days for the C2-WBRT + intrathecal treatment cohort, and 544 days for those receiving both systemic and intrathecal treatments with C2-WBRT. Both the combination of systemic and intrathecal treatments and the systemic treatment alone showed significant survival benefits over intrathecal treatment alone in C2-WBRT-treated BC patients (p=0.011; p<0.001). However, the addition of intrathecal therapy to systemic cancer treatment did not provide a survival benefit in C2-WBRT-treated BC patients (p=0.209). Conclusion: These data provide valuable insights into the impact of antineoplastic therapy prior to and after C2-WBRT for MC patients. NSCLC patients benefit significantly from additional antineoplastic cancer treatment parallel to C2-WBRT. Furthermore, systemic treatment shows benefits over intrathecal treatment in BC patients, indicating that BC patients with MC and C2-WBRT do not profit from intrathecal therapy.

Keywords: Meningeosis carcinomatosa, WBRT