SDPS-37 IDENTIFICATION OF TIME-COURSE RELATED, TREATMENT-RELATED, AND PATIENT-RELATED PROGNOSTIC FACTORS IN BRAF-MUTANT MELANOMA BRAIN METASTASES.

PURPOSE: Patients with BRAF-mutant melanoma brain metastases (MBM) continue to have limited overall survival (OS), averaging 4 months, despite advancements in systemic therapies. Our study aims to identify patient-specific and treatment-related prognostic factors in BRAF-mutant MBM to inform treatment sequencing and patient selection in future studies and improve patient outcomes. METHODS: The following data were manually curated from 100 patients with BRAF-mutant MBM diagnosed from 2009-2018, with primary cutaneous melanoma and who received initial MBM treatment at our institution: clinical and demographic, treatment, and OS outcomes. We compared OS with the log rank test using the Python package kaplanmeier between the various clinical, demographic and treatment (including treatment sequence) related variables. RESULTS: Both elevated lactase dehydrogenase (LDH) was associated with shorter OS (p=0.023), as was leptomeningeal disease (p<0.001). Gender (male vs. female) and initial treatment modality (BRAFi vs. immunotherapy) did not significantly impact OS, (p=0.911 and 0.578, respectively). Breakthrough brain metastases were associated with shorter OS for patients who received initial systemic therapy for MBM (p<0.001), but breakthrough metastases did not significantly impact OS for the whole cohort (p=0.141). Additionally, patients who received BRAFi before MBM diagnosis had shorter OS (p=0.028). CONCLUSION: In conclusion, we have identified some interesting relationships between OS and the sequencing of treatment modalities, as well as the timing of MBM presentation. These findings support further investigation of treatment sequencing to improve outcomes and the consideration of clinical variables, disease presentation, and treatment history to help refine patient selection for future trials for patients with BRAF-mutant MBM.