P17.26.B CLINICAL DATA ON INTRACRANIAL CONTROL, OVERALL SURVIVAL, AND TOXICITY LEVELS IN PATIENTS WITH BRAIN METASTASES TREATED WITH SURGERY, RADIOTHERAPY, AND VARIOUS SYSTEMIC THERAPIES-ONE CENTRE STUDY.

Abstract BACKGROUND Brain metastases (BM) treatment requires an interdisciplinary approach encompassing local therapies as neurosurgery and radiotherapy, as well as systemic therapies, including chemotherapy, immunotherapy, targeted therapy, and combination regimens. In this study, we evaluated progression-free survival (PFS), intracranial control (IC), overall survival (OS), and toxicity levels associated with these treatment modalities. Decisions regarding each treatment option were made by our interdisciplinary tumour board. All patients included in the study had previously undergone surgical resection of at least one metastasis and radiotherapy. MATERIAL AND METHODS A total of 114 adult BM patients were retrospectively analysed (data collection from 2017 to 2024). Patients were divided into three main groups based on the systemic therapy received: chemotherapy group (CT n= 31), immunotherapy/targeted therapy group (IT/TT n= 40), and combination immunotherapy/targeted therapy and chemotherapy group (IT/TT+CT n= 44). Progression was assessed through MRI scans every three months according to the RANO-BM and iRANO criteria. Toxicity was evaluated using CTCAE. Kaplan-Meier estimates were used for calculating OS and PFS, while toxicity and intracranial progression were analysed using cross-tabulation. RESULTS Kaplan-Meier analysis revealed longer PFS in the IT/TT+CT group (591 days), than in the CT group (284 days) and IT/TT group (523 days) with a Tarone-Ware test p-value of 0.055. OS demonstrated a trend towards improvement in the IT/TT group (1080 days) than the CT group (959 days) and the IT/TT+CT group (800 days) with a Tarone-Ware test p-value of 0. 086. The most common toxicity level across all groups was Grade 2. For 19 Patients we had no documentation of toxicity. There were no significant differences observed among the groups (Pearson’s Chi-square p = 0.116). No significant differences in intracranial progression were observed throughout the follow-up period (Pearson’s Chi-square test: p = 0.168), with progression occurring in 22 cases within the CT group, 26 in the IT/TT group, and 23 in the IT/TT + CT group CONCLUSION Although intracranial progression occurs in most patients with BM regardless of systemic therapy, longer PFS is observed in patients treated with the combination of immunotherapy and chemotherapy. OS shows a slight trend towards improvement in patients receiving immunotherapy. Importantly, the combined treatment approach does not appear to increase treatment-related toxicity. These findings underscore the potential advantages of combining immunotherapy with chemotherapy, offering improved outcomes without additional toxicity for patients with BM.